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5-1-1992
Spectral analysis of heart rate variability:
Acquisitionalysis software development
David James DeLong
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Spectral Analysis of Heart Rate Variability:
Acquisition/Analysis Software Development
by
David James DeLong
A Thesis Submitted in Partial Fulfillment
of the Requirements for the Degree
of
MASTERS OF SCIENCE
in
Mechanical Engineering
Approved by:
Mark H. Kempski, Ph.D. (Thesis Advisor)
Rochester Institute of Technology
Brahm Goldstein, M.D. (Medical Advisor)
University of Rochester Medical Center
Edward R. Salem, Ph.D.
Rochester Institute of Technology
Joseph S. Torok, Ph.D.
Rochester Institute of Technology
Charles W. Haines, Ph.D. (Department Head)
Rochester Institute of Technology
Department of Mechanical Engineering
College of Engineering
Rochester Institute of Technology
Rochester, New York 14623
May 1992
Title of Thesis
Spectral Analysis of Heart Rate Variability:
Acquisition/Analysis Software Development
I, David James DeLong, grant permission to the Wallace Memorial Library to
reproduce my thesis in whole or in part. Any reproduction will not be for commercial
use or profit.
The author makes no claims as to the reliability of the methods, procedures, or results
within the enclosed report for the purposes of medical diagnosis, treatment, or prognosis
of any human or other living organism.
Date
Abstract
This
the
work
develops
the heart
spectral content of
diographic
(EKG)
the
within
into
variability
The location
waveform.
head trauma
spectral content of
els of serum
the heart
rate
variability
frequency
activity
and strength of
the study
have
variability
the
Current investigations
subject.
revealed specific
as
both trauma severity
frequency
body
fact,
interest in the
band (0.01-0.15
temperature
adult)
of parasympathetic
a prominent peak
represents
Clinical
has
shown
heart
Hz)
application of
that
proved chances
elevated
and
Acute
and spectral power
power spectral
the
high
systemic arterial
The
levels
have
blood
a characteristic
at
of
critical care
neurophysiology.
respiratory
at
severe
shown
frequency band
indicator
medicine,
nervous system
as well
frequency band
sinus
arrhythmia)
a normal
is
only.
human
the respiratory frequency.
techniques
described herein
of
im
brain injury. In contrast, brain-dead
pe
found to
little
power are
possess near-zero
that decreases in
pressure with
density
regulation)
approximately 0.20 Hz (of
low-frequency HRV
change
low-frequency
low-frequency
in
indicative
HRV
high-frequency
power.
power and
HRV power,
of endotoxin-induced septic shock.
acquisition/analysis package
beneficial to
as
pressure
The high
acquisition and analysis
patients were
animal studies
may be
the
blood
system activity.
variability
for recovery from
diatric head trauma
and arterial
activity (such
located
rate
are also
signal.
some parasympathetic nervous
indicative
In
as
The lev
norepinephrine,
(0.15-0.50 Hz). The low frequency band is indicative of sympathetic
activity (such
between
correlations
and overall patient recovery.
epinephrine and
regions are of particular
waveform, the low
an electrocar
sympathetic and parasympathetic
a possible correlation with
rate
derived from
content
catecholamines, specifically
investigated for
the heart
patients
signal
to investigate
frequency
autonomic nervous system of
pediatric
Two
rate
information concerning
reveals general
of
an acquisition/analysis software application
described in this
and advance our
work
may,
understanding
therefore,
prove
of cardiovascular
Acknowledgements
The task
tribulations
completing this
during
appreciation
the
of
would
University
academic career.
would
of
and
like to
machine are
like to
challenging
extend
my
experience of all
thanks
greatest
guidance and monumental patience
of
and
during
the Pediatric Critical Care Center in the
Rochester Medical Center for allowing
head trauma
extend
greatly
my
neering Department for his
theory
would
like to thank Dr. Brahm Goldstein
the human
I
I
most
this thesis.
research work on pediatric
of
has been the
to Dr. Mark H. Kempksi for his
completion of
I
my
work
its applications,
His
the opportunity to
efforts
assist
in his
towards my understanding
appreciated.
sincere
efforts
patients.
me
thanks to Dr. Edward Salem
towards my understanding
without which
this
of
work could not
of
the Electrical Engi
digital
be
signal
processing
accomplished.
Contents
Abstract
i
Acknowledgements
ii
Table
v
of
Contents
List
of
Figures
List
of
Tables
1
ix
Introduction
1.1
1.2
2
viii
1
Mechanics
the Cardiovascular System
of
1
1.1.1
Physical Components in the Cardiovascular
1.1.2
Cardiovascular Function
1.1.3
Timing
1.1.4
Regulation
Mechanisms
Psuedo- Periodic
1.2.2
Psuedo- Periodic
of
Variability
Background
of
Heart Rate
1.4
Justification
of
Research
Humans
1.4.2
Potential
of
Cardiovascular
in Physiological Waveforms
Cardiovascular Variations
1.3
of
Cardiologic Events
Variations in Physiological Waveforms
Origins
Use
3
Feedback Mechanisms
and
1.2.1
1.4.1
of
4
Activity
.
9
16
17
18
19
Variability
23
and
use as a
1
system
23
Rabbits
Diagnostic
and
Prognostic Tool
24
25
Methodology
2.1
Methods Employed in Previous Experimental Work
25
2.2
Preparation
Subjects
27
2.3
Collection
Physiologic Data
29
2.4
Analysis
of
of
of
Study
30
Physiologic Data
in
3
4
Detection
2.4.2
Creation
2.4.3
Power Spectral Analysis
2.4.4
Respiratory Frequency Verification
44
2.4.5
Statistical Analysis
44
of
of
QRS-Complexes
the HRV Signal from R-wave Peak Location Data
of
the HRV Dataset
Results
31
.
.
39
42
46
3.1
Pediatric Brain
3.2
New Zealand White Rabbits
47
3.3
Software Application
47
Injury Patients
46
Discussion
4.1
4.2
5
2.4.1
55
Acquisition/Analysis Software Development
4.1.1
Hardware Requirements
55
4.1.2
QRS Complex Detection
57
4.1.3
Respiration Signal Analysis
60
4.1.4
Application Features
64
4.1.5
Software Limitations &: Operational Notes
65
Clinical
Conclusion
and
and
Result Interpretation
Laboratory
Appendix A
A. 2
-
Signal
71
Processing
Continuous-Time
Analog
A. 1.1
The Fourier Series
A. 1.2
Spectral Content
Fundamentals
of
76
76
Signals
76
Analog
Signals
78
83
Discrete Signals
A. 2.1
66
60
Recommendations
References & Citations
A.l
55
Discrete Fourier Transform
IV
84
A. 2. 2
A. 3
A. 4
Spectral Content
Considerations
of
the
of
Spectral Abberations
A. 3. 2
Reducing
Appendix B
Appendix C
Appendix D
Appendix E
-
-
-
-
89
Discretization Process
A. 3.1
Power Spectral
88
Discrete Signals
90
Spectral Abberations
92
Density Determination
94
Rabbit Endotoxin
Study
95
Grant Proposal
101
Related Published Abstracts
Sample Program Output for
Software Design
and
a
Program
Normal Analysis
Operating
Manual
107
115
List
of
Figures
1
The human heart in functional
2
Schematic
3
A typical lead II EKG
marking distinctive
4
An
5
actual
representation of
EKG
the EKG
superimposed on
the
event series
tion
A Comparison
from the EKG
7
Example
8
A QRS
representing R
of
9
during
that
cardiac
the
5
A QRS
relative
waveform stage
complex
Example
activity is
respiration
activity (the pulse) is
9
peaks
in the EKG (a). R-R interval dura
by a
obtained via
interpolation
1987)
sizes
26
of
to the
'blocks'
used
33
zoom-window stage
EKG tracing
an
scan-
the data processing
window edge.
and point
R
35
Point L
marks a
left
window
marks a right window edge slice
37
detected
the
near
of computer processed
A
'left'
to include 95
adjustment
glitches at points
Example
and
B
of computer processed
edge of
points
the first
is necessary
instantaneous heart
the
are
rate
result of glitches
IHR dataset
scan-window.
37
(IHR)
dataset.
in the EKG
after application of
signal.
40
Changes in
jured
power spectral
patient with
cerebellar
40
the IHR. Patch
algorithm
12
8
cardiac cycle.
the R-S interval
The
11
the
the Q-R interval
Zoom-window
10
of
complex sliced
edge slice of
points
the heart
respiration signal
large T-waves in
of
system of
tachogram (b). Interval function
series or
2
tracing. Note that
signal and
(c). (Reproduced from Baselli
6
form
the conduction
and respiration
superimposed on
An
schematic
GCS=3
herniation
magnitude of
and
the Y-axis
density
(top)
of
and
HRV in
the
a
four-month
same patient
brain death (bottom).
old
brain in
24 hours later
after
Note lOx difference in
50
scales
vi
13
Temporal
brain death.
Temporal
of
interfered
15
An
in
changes
brain death.
with
the
EKG
example
rate power approaches zero
plasma catecholamine
almost
waveform
levels
in 2/3
non-detectable
catecholamine
of
in 3/3
51
(pg/ml) during
norepinephrine
The third
the development
during
brain death
and
brain death. Plasma
levels become
opment
total heart
tonsillar herniation
velopment of
(E)
rate power spectra
Low-frequency
patients with
14
in heart
changes
patient
was
(NE)
patients
the de
and epinephrine
with
the devel
receiving dopamine that
52
assay
illustrating
anomalous occurrences
in the
sec
58
ond panel
16
An
anomalous point at
cs
34
seconds
in
an example
EKG tracing
59
17
An
anomalous point at ss
40
seconds
in
an example
EKG tracing
60
18
Extraction from {IHR.
in
EKG
example
FIR digital filter
Plot
A-l
Example
of
A-2
Example
of summed
A-3
The
A-4
The two-sided
three
Note that
Representation
A-6
The
periodic
A- 7
The
by
(composite)
of a
is
of
index
63
79
signals
79
signal
spectrum
discretely
nature
analog
spectrum of
frequency
the DFT
effect
frequency
the
The
example
function
composite
analog
record
.
waveform.
is
an odd
function.
.
resulting from the
assumptions
87
of a
non-integer
number of cycles
in
a
90
sinusoid signal
A-8
Leakage
effects
in the
'windowing'
effect of
81
83
signal
algorithm
in the time domain
80
with amplitudes one-half
phase spectra
sampled
the time
example composite waveform.
the
of
an even
one-sided spectrum.
A-5
made
mono-
amplitude spectra
those for the
points
61
coefficients versus coefficient
frequency
one-sided
illustrating effects anomalous
waveform
19
of
dataset
Values}
frequency domain
to
minimize
it
vn
of a
mono-frequency
sinusoid and
91
A-9
The
effect of
windowing in the time domain
vni
93
List
1
of
Tables
Age,
sex, Glascow Coma
Score, basal
cardiorespiratory parameters, heart
power spectral values and plasma catecholamine
2
Cardiorespiratory,
after cold pressor
3
Changes in
power spectral and catecholamine
testing. Data
in the New Zealand White
4
Hardware
5
Disk file
expressed as mean
various physiologic parameters
used
rabbit,
for development
storage requirements
(mean
S.E.M).
levels (mean
changes
before
and
49
S.E.M
resulting from
endotoxin shock
53
S.E.M.)
55
versus actual application use
for D/A integer data for
nominal
256
subfile
56
recording
A-l
Comparison
48
of
the Number
of
Real Multiplications for the DFT
IX
and
FFT.
88
1
INTRODUCTION
1
Introduction
1
Short-term
ships
in
variations
cardiovascular
between the circulatory, neural,
of an abnormal physiologic
The human
The
The focus
affected.
the
is
following
responsible
sections
for the distribution
is to
brief
present a
Physical Components in the Cardiovascular
The
cardiovascular system
sels.
The heart functions
form the distribution
of
consists
network
systemic
is
composed of
as a positive
network
be
during
on
head
of
blood in the body.
overview of
the
normal
through
the heart
and a complex network of
displacement 'cardiac
which
blood
of
blood to the lungs
and
pump'.
moves about
the
body,
and
blood
The blood
the body. The
veins, in
ves
vessels
vascular
order of
through the pulmonary
flow
and
circulations, respectively, is depicted schematically in Figure 1. The pulmonary
circulation
delivers deoxygenated blood to the lungs for
circulation
provides
To
provide
oxygen
pump
and
timing
properties which are modulated
pulmonic
and
action
of
nutritional
and
by
which
the heart
is
must
support
external neural
networks
largely
reoxygenation.
for tissue
control, the heart
systemic vascular
flow. Vascular impedance,
pumping
system
arteries, arterioles, capillaries, venules,
from the heart. The flow
The
these bi
present work will
and abnormal control
activity,
event
cardiovascular system.
1.1.1
mands.
In the
and regulation of
the
of
the body.
the Cardiovascular System
of
cardiovascular system
main purpose of
human
by functional inter-relation
and sepsis conditions.
Mechanics
1.1
interaction
normal
cardiovascular control via autonomic neural
trauma
determined
are
and endocrine systems of
condition, the
may be adversely
systems
ological
activity
systemic
metabolic
de
possesses spontaneous contractile
impulses.
impart
vascular
resistive, is the
overcome.
and organ
The
The
impedance to blood
afterload against
magnitude
of
the
which
the
is
dy-
afterload
1
INTRODUCTION
lining
nside
of
heart
(ndocardium)
RIGHT HEART
receives
tEFT HEART
blood from the
receives
body
and
pumps
it
to
artery
where
if
the
picks up
oxygen-full
blood from the lungs
through the pulmonary
and
lungs
pumps
it through
the aorta to the body.
fresh
oxygen.
bag
TRUNK
&
LEGS
Figure 1: The human heart in functional
Heart
Association, Inc.)
schematic
of
tissue
surrounding heart
(pericardium)
form.
(Courtesy
of
the
American
INTRODUCTION
1
adjusted
namically
3
primarily
by
the
for
arteriole's smooth muscle accounts
tered tissue
oxygen and nutrient
the
smooth muscle of
adjustments of
blood
demand. Adjustments in
The
arterioles.
tone1
the
of
in
response
to
afterload will
therefore
affect
delivery
al
cardiac output and performance.
Neurologic,
be
obtained
physiologic, endocrine,
from physiology texts.
human physiology
within
this
are covered
tissue,
1).
The
right
tricuspid valve,
the
points of
cursory
interest concerning
below to facilitate understanding the
mitral valve.
pulmonic
consists
the left heart
The pulmonary
the
and
value,
The heart is
material
of
the
anatomically
right
consists of
the left
vasculature
systemic
atrium
vasculature
is
discussed
and
fibrous
consists of
functionally
and
by
the
by
supplied
connec
two
distinct
interfaced
ventricle
atrium and ventricle
supplied
is
comprised of
The heart
and a neural network.
chambers which are
heart,
and
Function.
and
tissue,
cardiac muscle
two interconnected
ure
some
function may
work.
General Heart Structure
of
However,
of cardiac
Cardiovascular Function
1.1.2
tive
details
and pharmacologic
pairs
(Fig
by
the
interfaced
by
right
ventricle via
the
the left
ventricle via
the
aortic valve.
The
contraction
of
the
monary artery (from the
body
locations. The
compliance and
This 'hydraulic
'Tone is
and
ventricle can
into the
be felt
filter'
dampens the
is
attenuated
capillary
nearly steady
overall
Higher impulse frequencies
(non-pulsatile) [7,
by
The
vascular wall
networks
pulsed nature of ventricular output
where oxygen and nutrients are
pul
as an arterial pressure pulse at various
peripheral arteriole and
capillaries remains
the
(from the left heart).
aorta
pulsatile nature of ventricular output
a qualitative measure of
neural pathway.
initiates blood flow from the heart into the
heart)
frictional losses in
flow reaching the
capillary level
right
from the left
periodic efflux
ventricles
such
p486].
[7,
p395].
that blood
It is
at
the
transferred from the blood to the tissue
frequency
of nerve
impulse activity
elevate muscular/neural
tone.
within a muscle or
1
INTRODUCTION
4
and metabolic waste products are removed
and
aorta
blood
has very
additional
There is only
Change in
elastic walls which
Subsequent diastolic
pressure.
discharges
the
blood into the
in
drop
a slight
arteriole caliber
arterial pulsatile
recoil of
during
eventual
The pump function
of
aortic wall
capacitively
systemic circulation.
arterial
Active
of
due to increased flow
systole2
the distended
blood
the
pressure until
resistance and
is
arterioles are reached.
regulated
regulation of arteriole caliber
flow to quasi-steady flow in the distal
Timing Mechanisms
demand through
distend
strongly impacts flow
autonomic nervous system3.
1.1.3
for
blood)
from the body.
excretion
The
from the tissue (into the
primarily
effectively
by
smooths
capillaries.
Cardiologic Events
the heart is precisely
concomitant shifts
in
controlled
cardiac
to
accommodate
beat-to-beat
output4
over
metabolic
shifting
and extended
time frames.
Cardiac tissue has
is known
[7,
as
rate of
[7,
ity
rhythmicity
node,
2
p399]; the
(sis'to-le)
is the
ventricular
filling
and
hence,
systole and
diastole to
occur.
3The
4
output
about
thus termed
90
as polarized.
is denned
of ventricular
period
relaxation.
as
and
millivolts
A 'cardiac
the
product of
the heart
value.
its function. Internal
negative with respect
The highest
Diastole
encompasses
on page
rate and
The
potentials
to the
cell
orders of automatic
the
atrioventricular
activity (Figure 2).
cycle'
is described in Section 1.1.4
rhythmicity
a zero or positive
cardiac
contraction.
as
tissue to contract, implies that
sinoatrial node and
importance in regulating
autonomic nervous system
Cardiac
depolarizations is known
the tissue type
found in two areas, the
which are of prime
Systole
upon
normally
cells are
are
of
approaches, from the negative,
cells are
surface
to spontaneously depolarize. This property
which causes cardiac muscle
depolarization depends
tissue
characteristic
the regularity
and
automaticity
voltage potential
of cardiac
and
innate
Depolarization,
p409].
a cell's
an
the
(di-as'to-le)
the
is the
period of
period
time for both
10.
stroke volume
[7,
of
p534].
1
INTRODUCTION
Superior vena
cava
Sinoatrial
node
Right atrium
Atrioventricular
node
Right
ventricle
/
purkinje fibers
Papillary musde
Figure 2: Schematic
from Berne
[7,
representation of
p414])
the
conduction system of
the heart.
(Reproduced
1
INTRODUCTION
Sinoatrial Npdq.
superior
and
6
The
the
vena cava and
receives
order
depolarizes,
spontaneously
the
cardiac
of
rhythmicity
by
or
heart's internal
neural network
into the left atrium,
initiating
blood from the
into the
atria
Atrioventricular Node.
surface
at
the lower
various
the
node
be
The
slower
signal
of
its
the
initiate
than the
natural
from the AV
myocardium.
own
reduced
p410j.
This
delay
cardiac
by
the
The SA
system.
p410].
has
node
associated cells
which
initiates the
impulses through the
the
across
spreading
node
When the SA
stimulation,
of neural
distally
in
or
right
atrium,
contraction expels
the
AV node, located
(Figure 2),
neural
allows
second
activity
depolarization
node moves
conduction rates
on
the
anterior
the spreading
differing
conduction
neural
speeds
impulse is slightly delayed before
for
optimal
highest
should
rate of
filling
order of
of
the
ventricles
rhythmicity
of all
incident impulses from the SA
the AV
node or
interrupted.
though the Purkinje fibers from the interventric
a prescribed manner
per
receives
due to
causing
Should incident impulses from the AV
frequency (30-40 beats
regulated
the heart
of
(see Figure 2). This
Normally,
node.
rhythmicity, the Purkinje fibers
The impulse
fashion,
atrium
which possesses
also
ular septum outward or
a radial
right
The AV node,
may
[7,
between the
'pacemaker'
depolarization
discharge
a
atrioventricular
[7,
tissue,
right atrium
ventricles.
ventricular contraction.
cardiac
effects
in the AV node, the
regions
tissue
electrical
atrial contraction
The
end of
in
triggering
p414].
cardiac
nervous
autonomic nervous system
impulses originating from the SA
through
of all
This depolarization
cycle.
autonomic
chemically induced
node effect a
the
on
(Figure 2), is the intrinsic
aorta
impulses from the
neural
the highest
within
SA node, located
sinoatrial or
can
initiate
autonomic nervous system.
be
absent or slower
ventricular contractions at
minute) than that
throughout the
node
progressive contraction
of
the SA
or
AV
neural network of
than
a much
node rates
the heart
can
[7,
be
1
INTRODUCTION
Measurement
piration
to
rate,
7
Physiological Activity.
of
autonomic
effect patient
These
state of a patient.
Normal
when
possess
properties
sented as electrical potential changes
the skin,
of sensor electrodes on
This
activity.
EKG (also
ECG)
An EKG
the
ment of
electrical
waveform
labelled
cardiac
The initiation
heart
cycle
of atrial
and
timing
100
complex
repolarization of
is formed
by
between the
and
seen
to
physiologic
cardiac
tissue
and
the
activity,
monitored.
tissue
skin
repre
Placement
of cardiac electrical
produce an electrocardiogram or
dependant
[7,
node as
basis,
which
shoulders
right shoulder and
as
('firing'
and
and
of
number and place
typical lead II
the SA node) is indicated
is the focal
The duration
The
interval
dis-
EKG5
point
of
elapsed
and
is
indicates
the P-
by
onset of ventricular
in this study for extracting
the
QRS
complex
is normally
time between the P-wave
caused
by
the
delay
of
the
and
cardiac
The T-wave is indicative
of
the
after contraction.
'triangle'
of a
the
points on a
complex which
the time between
leg
the
cardiac cycle are common and
mentioned previously.
tissue
upon
illustrated in Figure 3.
p422].
P-Q
the
by distinctive
is the QRS
information.
cardiac
type denotes
T
contraction
is termed the
the
the two
marked
milliseconds
beat-to-beat
5The lead
is
the AV node)
of
through the AV
a
recorded
certain attributes of
P, Q, R, S,
as
('firing'
contraction
the QRS
On
but
The dominant feature
between 60
signal
activity is normally
the
the
neural
for the monitoring
allows
performed
non-invasive methods.
body
be
res
signal.
electrodes
The
contraction
therefore,
can
about
within
resistance, this
in the thoracic cavity,
signal possesses specific attributes
cernable.
wave.
the heart. Since
and
conductivity
activity
rhythm,
continuous-time mea
information
significant neural
of cardiac
is routinely
pressure
In particular,
can elicit
moves across
of electrical
blood
routinely done through
measurements are
'wave'
and
and prognosis.
respiratory activity
function involves
cardiac
depolarization
the
tone, blood chemistry,
diagnosis, treatment,
surement of cardiac and
Clinical monitoring
pubic
the lower left
is
region
chest.
successive
used
or
for the
lower left
R-wave
peaks
(Figure 3) has
signal measurement.
chest.
Lead II
This triangle
represents
the
path
INTRODUCTION
1
Figure 3: A typical lead II EKG marking distinctive
(Reproduced from Berne
been
observed
to vary
[7,
by
time-averaged indicator
rate
many
milliseconds.
of cardiac contraction.
(in beats/minute
or
successive
BPM)
can
The
In
The
skin
Hence,
the
monitored
by
stretched.
be
can
within
chest
R-wave
displays
most
a certain
serum
often
of
determined
property that
cycle.
an
is simply
mean value of
changes
and expiration.
EKG
a
the time
EKG trace, the
mean
of
beats
(1)
Elapsed time
exhibits
a
brought
This
effect
in resistivity
change
the
Note that
often a superposition of
chest
since
both the
about
by
during
when
respiration
the heart
pulsates
respiration and
EKG
volumetric changes of
is illustrated in Figure
4,
which
and respiration signals.
chemicals, gases,
by
(MHR)
rate
the
Number
these resistivity fluctuations.
inspiration
levels
cardiac
be determined from Equation 1.
relative expansion and contraction of
recordings of actual
Blood
at
from
peaks
Mean R-R duration
due to thoracic impedance
during
the
=
the thoracic cavity, there is
waveforms
the
possesses
heart
mean
looking
60
MHRB/W
during
p422])
duration (in seconds) between
heart
points
appropriate
and
hormones
laboratory
assay
(including
catecholamines)
testing using
extracted
are
blood
1
INTRODUCTION
samples.
000
3
'000
'a.
Figure 4:
An
.
the
1.1.4
The
respiration
the
spontaneous
cardiac output at
.
ee
'6.001
'00'
EKG
EKG
and
signal
9
*
&
be
.
1
.
.1
_
12.0
1
I
'9.00'
'xa'.B1
respiration
tracing.
that
and
cardiac
_l
I
is.o
'xa'V
Note that
1
I
I
ls.e
21.0
'is'V
'21'.
respiration
activity (the pulse) is
I
r
e
activity is
superimposed
signal.
Regulation
ods of normal
6
actual
superimposed on
on
ee
and
activity
levels
activity,
Feedback Mechanisms
of
the
SA
appropriate
and
to
cardiac output
AV
support
is
of
Cardiovascular
nodes
is generally
basal
metabolism.
modulated
by
Activity
sufficient
to
maintain
However, during
various physiologic stimuli.
peri
This
INTRODUCTION
1
is the
modulation
part,
the
within
greatly
10
result
of a
following
depending
upon
biological feedback-control
text. The demands
the level
and
type
the
of
body
internal
of
system
for
affecting the
timing, volume,
and strength of
Information concerning the
diovascular
activity.
information
and
blood
of
Blood chemistry includes
chemistry.
the
the
gathered
endocrine or
chemical
hormonal
feedback-control
Cardiovascular
and
vous system activity.
system and
gan
the
is
functions
responsible
include
per
to
car
collect
body temperature,
rate,
such as
oxygen and
other quantities.
many
carbon
Commu
These primary
pathways.
autonomic nervous system pathways and
systems
performance are
directly
form
a complex neural and
network.
autonomic nervous system
for the
subconscious
transient
physiological
autonomic nervous system
is influenced
during
in modulating
utilized
respiration
and
that
(contractility).
called receptors are used
Together these
system.
respiratory
The
is
information involves two primary
conveyance
stimuli
vary
must make minute changes
quantities
levels, hormone levels
pH
information
mechanisms of
current physiological state
blood pressure, blood volume,
about
external
contractions
Various biologic sensing devices
dioxide concentrations,
nication
its
oxygen and nutrients
and
turb homeostasis6. In
responding to this stimuli, the heart
is outlined, in
which
is
a subsystem of
monitoring
stimuli.
by
affected
autonomic ner
the
central nervous
and regulation of
The function
various
by
drugs,
internal
or
and performance of
chemicals,
and all of
the
physiological quantities mentioned above.
The
The Autonomic Nervous System.
two
subsystems of
distinct
neural
various metabolic activities.
and
the
internal
outside
the
environment
the
7The
These two
parasympathetic nervous
homeostasis:
system
tendency
while
[24,
of
pathways
simultaneously
which collaborate
subsystems
system7.
biological
autonomic nervous system
Most
systems
to
interacting
are
often
maintain
and
the
is
comprised of
and compete
to
sympathetic nervous system
a synergistic
relatively
adjusting to
relationship
constant conditions
changes
originating
p584].
parasympathetic nervous system
is
also
known
as
the
regulate
vagal nervous system or vagus.
exists
in the
within or
INTRODUCTION
1
between the
11
sympathetic and
(internal organs)
viscera
some
pathways,
only
and other areas of
by
the
body
sympathetic and parasympathetic pathways.
The
arterioles
but
are also
innervated
Both the
impulses
ral
(resistance vessels)
a small
innervated
the vagus,
The heart is
primarily innervated
are
proportion, in the genitalia,
by
are
bladder,
large
a parasympathetic nerve
the
only
and
dynamic internal
by
various receptors
physiological state
to
in the
appropriate control centers
significantly to the feedback
munication mechanism contributes
innervated
by
organ.
516].
Hence,
viscera.
sympathetic
salivary glands,
sympathetic and parasympathetic nervous systems support
collected
the
of
sympathetic nervous
bowel,
[7,
organs
dually innervated
a
by
by
dually
parasympathetic pathways, and some are
both
system
Some
parasympathetic nervous systems.
afferent8
neu
communication of
is
achieved.
This
the
com
control of cardiovascular
activity.
Chemicals
the
body
neurons
to
assist
Different
neural
of
the
utilize
across
Neurotransmitter Blockades.
neural pathways
a
gap (synapse).
neurotransmitters
pathway
synapses.
neural
blockades
directly
services.
across
for
8AfFerent
from the
stimulation
neural
or spinal cord.
are called
synapse
the
blockades
of
The
spinal
the
import
neural
cord
at
interfere
with
(neuro-blockers)
by
the
neurons
neurotransmitters.
the
and
synapse.
normal
their
Two
function
effect
is to
neurotrans
are atropine and propranolol.
pathways
various
of
the
sympathetic
elevations
sympathetic nervous system
increases
nerve cells or
sympathetic and parasympathetic
and chemicals which
which are of some
adjacent
produced and released
the
each of
between
impulses attempting to transmigrate the
The function
in general,
brain
chemicals
synapse are called antagonists or
Sympathetic Pathways.
extend
The
are used
Drugs
Neural impulses travelling through
and must often pass
in transmitting the impulses
impede the
mitter
and
metabolic activity.
With
impulses travel from the periphery in towards
nervous
for the different
differs
respect
system
organs
with some organs
to the
it
but
cardiovascular
central control centers
such as
the
INTRODUCTION
1
12
system, increased sympathetic
stoke
rate,
The
two
volume,
types
for
The
vessels
is
0i
/32
skeletal
subtypes.
receptor
contractility,
type is involved
tant to the
current
study
primarily innervated
(blockade)
used
for
by
blood
with
of
system extend
heart
viscera.
organs
but in
cardiovascular
maticity
[7,
general
of
The
norepinephrine.
the
of
the
cardiovascular
f3r adrenergic
blood
pressure and
rate
variability, The
The
nervous systems
9EfFerent
neural
in
a
respon
and
they
receptors.
synergistic,
and are
resistance-type
further
receptors result
work.
categorized
in increased
A
vascular smooth muscle.
volume
regulation,
smooth muscle of
the
and
This
is impor
vasculature
is
common neurotransmitter antagonist
is
propranolol.
neural pathways of
the
parasympathetic nervous
spinal
cord) into
parasympathetic nervous system also
differs
with some
(and the
decreases
region
sacral
for
affected
rather
by
synapses of
than
impulses travel from the brain
the
of
activity.
metabolic
parasympathetic efferent
neurotransmitter
is
in
a-adrenergic
the
stimulation
system
and
The
investigated in this
by epinephrine,
muscarinic and a common neurotransmitter antagonist
The
the eye,
of receptors are not
the brain
system, increased
p451].
by
muscles of
j3\- and /?2-adrenergic synapses
The function
type is
and cardiac conduction velocity.
/32-adrenergic
directly from
receptor
different neurotransmitter,
is prevalently found in the
Parasympathetic Pathways.
the
muscle, the
Simulation
02- adrenergic receptor
The
each use a
receptors are stimulated
in
sympathetic nervous system contain
beta (/?). Each
and
receptors are stimulated
myocardial
the
stimulation.
(arterioles). These types
and
heart rate,
type
(a)
tissue, they
to
automaticity, heart
cardiac
p451].
alpha
sites,
of
rates
prevalent
The /3-adrenergic
into the
type
different
a-adrenergic
receptor
blood
of receptor
a particular
each react at
type
[7,
contractility
activity increases
post-ganglionic adrenergic synapses of
major
sible
and
efferent9
or spinal cord out
to the
cardiac auto
parasympathetic system
is
atropine.
sympathetic
antagonistic
respect
activity inhibits
the
is
With
and
manner.
the
As
parasympathetic
an
towards the body.
example, if
a
INTRODUCTION
1
need
for increased
increase its
crease
flow
output
then decreases its
will
cardiac output
efferent
cardiac
13
of neural
a
only
cardiac output without
the
sympathetic nervous system will
impulses.
However,
If the
certain amount.
level
current
Therefore,
result.
arises, the
of efferent
act
actively opposing the
synergistically to
The tonic level
conditions
is
the
100 beats
Chemoreceptor Influences.
portance
(low
for the
oxygen
trigger
a response
account
for
respiration
account
about
[7,
from the
70-80%
p627].
with oxygenated
alter
per minute
Chemoreceptors
blood
[7,
The
chemoreceptors.
of
the
are an
The
effects on cardiac
response
[7,
important
The
physiologic
rate of
p451].
levels
of various chemicals and
is
directly
levels
im
concentration) both
central chemoreceptors
carbon-dioxide
(in the
are of most
involved. Hypoxemia
carbon-dioxide
activity for
(in the medulla)
induced increases in
carotid10
and aortic
bodies)
p627].
element
in the
maintenance of perfusion of
blood. Autonomic impulses resulting from
volume,
under
and carbon-dioxide
peripheral chemoreceptors
pressure and
overall
sympathetic and parasympathetic
monitor
hypercapnia (high
for the remaining activity
Chemoreceptors
may
and
has increased the
'normal'
pathways,
cardiovascular system since respiration
concentration)
cardiac output
simultaneously, the intrinsic heart
in the circulating blood. Oxygen
compounds
further increase in
may have opposing
If both
non-zero).
are administered
adults averages about
and
subsequently
the brain
chemoreceptor stimulation
affect autonomic cardiovascular
neural activity.
10The
carotid sinuses and
the
carotid
in
parasympathetic nervous system
sympathetic nervous system's action.
autonomic nervous system
blockades
will
alter cardiac output.
insignificant (i.e.
not
neurotransmitter
young
of
sympathetic stimulation
parasympathetic nervous system
sympathetic and parasympathetic nervous systems
activity but
a
activity,
normally
bodies
are near
the internal
carotid arteries within
the
neck.
1
INTRODUCTION
14
Respiratory Influences.
respiration
the
centers of
Control
brain,
parasympathetic pathways
hypercapnia increase
walls of
respiratory
The
the
effect
of respiration
The
most
as
inspiration
[7,
and
which
receptors, in the
of
the lungs
pons, through
Both hypoxia
increases
respiration
inspiration
and
rate
layer in
smooth muscle
during
the
by
exerted
and
impact
blood
lies in two
primarily includes
The
and expiration.
nervous
neurological effects
the tho
include
changes
Variations in the heart
mechanical and neurological
Respiratory
arrhythmia.
mechanical and
pressure changes within
system.
these
areas:
sinus
arrhythmia
at
rate
influences,
is
is detectable in
p456].
pressure
Blood
Two
afferent
principle
information
information is detected
pressure
Baroreceptor
parasympathetic system.
arterial
activity
cardiac performance
as a result of
sinus
respiratory
baroreceptor.
a
the inflation
parasympathetic
frequency,
individuals
on
Baroreceptor Influences.
called
called stretch
mechanical aspect
the
of
respiration
known
medulla oblongata
chemoreceptor stimulation.
afferent parasympathetic
airways monitor
during
cavity
in the tone
the
to
response
activity is primarily
activity.
neurological.
racic
specifically the
Mechanoreceptors,
and volume.
the
in
of respiration
impulses
are
locations in the
and
are
by
conveyed
a
type
of neuron
the
via
primarily
cardiovascular system contribute
located in the
arch
aortic
and
the
carotid
sinuses.
Heart
arterial
the
rate response
blood
is
inversely
pressure variations.
related
This
to
changes
response
is invoked
sympathetic and parasympathetic nervous system
the direction
than 20-30
rate).
the
pressure
mm
Hg,
cardiac
When
change.
sympathetic
After which, further increases in
in further
blood
of
reductions
pressure.
A
in heart
small
rate.
in blood
arterial
by
pressure within normal
reciprocal changes
activity, the
blood
tone is completely
net effect
pressure
pressure elevates parasympathetic
The
decline in blood
opposite
pressure
affect
will
occurs
decrease
for
depends
increases
suppressed
in both
on
by
more
(lowering
heart
tone, resulting
decreasing
arterial
parasympathetic
tone
1
INTRODUCTION
and
15
thereby increase heart
heart
is solely
rate which
rate.
attributable to
Blood Volume Influences.
atrial
ate
(and hence cardiac)
the heart
blood
[7,
p455].
invoke this reflex,
which
pressure
Stretch
increases in
diastole.
of change
Blood
in heart
is known
the Bainbridge
as
Vascular Flow Resistance Influences.
flow
vascular
ulating
(a
neurons
and
riolar caliber.
/32) innervate
Increased
lation, depending
the
current
pressure
(skin)
tissue
may
the
need
by
the the
[7,
extremities.
with
the
for
regulation of
volume,
vous
be
autonomic
serum glucose
augmented or
One category
drenaline)
Subsequent
Changes in
and
of
cells
in the
humoral
is
(sugar) levels,
and
hormones
and epinephrine
by
various
are
the
drugs
and vasodi
imparted due to
stimulation
increases in
linked
arterial
with
and constriction of
the
blood
cutaneous
the blood
arterial
blood
above.
cardiovascular
performance origi
normally function synergistically
hormones in the
and sympathetic
in reg
regulates arte
actually
described
response
activity
can
Sympathetic
pressure.
directly
the dilation
Circulating
systemic
elements
either vasoconstriction
body
body
acceler
hemorrhage
or
vascular resistance often change
effectiveness of endocrine
of
in
reductions or
the
in
changes
primary
blood
arterial
metabolic activities some of which
diminished
infusion
volume
of
reflex.
The hormones affecting
nervous system.
many
system, the
results
illicit the baroreceptor
glands
assorted
by
arterioles are
specific neural or
p513].
The Endocrine System.
from
tone
sympathetic
by
p454].
the degree
monitor
unaffected
vascular smooth muscle which
sympathetic regulation of
pressure and as a result
nate
this
Thermoregulation
result.
circulation
vessels of
upon
The
thereby affecting
resistance
is
incurred
volume changes
atria
[7,
tone
sympathetic
Increases in blood
rate
accelerated
pressure promote an
in both
receptors
filling during
This type
rate.
Further decreases in
include
tone. As
body
osmotic
with
the
on cardiovascular
are responsible
balance, blood
autonomic ner
performance can
and chemicals.
catecholamines which
(adrenaline). Epinephrine is
include
released
norepinephrine
by
the
(nora
adrenal medulla
1
INTRODUCTION
and
its
marily
rate,
presence elevates cardiac
stroke
ways,
16
volume,
released
and
by
induces
Circulating
and
contractility,
it induces
conduction
arteriolar
dilation
catecholamines are used as neurotransmitters
reabsorbed
sympathetic nervous
of
Norepinephrine is
p979].
pri
arteriolar vasoconstriction.
is partially
the level
[7,
cardiac neural path
Norepinephrine increases blood pressure, heart
sympathetic neurons.
by
the tissue. Excess
is
catecholamines
circulating
a
is
norepinephrine
method
of
by
released
circulating blood
by
system synaptic clefts
and
assessing
facilitators
synaptic
and
Norepinephrine
which affect autonomic nervous system activity.
neurons
velocity in
sympathetic
away from
washed
hence,
monitoring
sympathetic
nervous
system activity.
Psuedo- Periodic
1.2
Many
continuous-time physiologic waveforms of cardiovascular origin are pseudo-periodic
in their
nature
rest, may
[4].
To the
observed.
Rhythms
casual
to be
appear
from
for
Variations in
years.
by
Hales
R-R intervals
yield a mean
short
arterial
heart
blood
an
question
heart
rate
logical
value.
of
questions
causing the
many
specified
not
In observing these
a pattern
that
studies of which
to follow involve
oscillations.
(EKG)
time
(see Equation 1). Upon
may be: 'Is there
been the focus
and
respiration
close
fluctuations
scrutiny
which
have been
are
the
recorded when
However,
period
pressure
electrocardiogram
observed over a
rate
durations.
reveal periodic
individual R-R interval durations may
mean
the heart beat
as
most
easily
subject
of
is
heart
at
rate
have been known
observed
as
early
as
4].
For example, if
of
for
individuals
healthy
[1,
such
observer, these waveforms, if
periodic
waveforms
1733
Variations in Physiological Waveforms
be
duration, by
closer
equal
to, but
to these
answer
determining
of
of
this
the
This
about, the
times,
the
one
question
affirmative.
of pattern and
will
EKG, however,
the R-R interval
oscillations?'.
number
duration,
rather oscillate
has been the
the type
of
that time
inspection
oscillations
exists
the
is scrutinized, division
The
has
next
mechanisms
1
INTRODUCTION
1.2.1
Origins
of
17
Variability
in Physiological Waveforms
The human
body
to
maintain
homeostasis. This interaction involves
of
function,
system response
is
is dependent
a system which
time,
and
upon significant subsystem
cascade-
system
interdependence, duplication
Examples for
effects.
interaction
each are
shown
below.
Interdependence:
Release
gered
of epinephrine
by
from the
endocrine system
is trig
sympathetic nervous system stimulation of
the
adrenal medulla.
Duplication
of
function:
Release
by
of epinephrine
bloodstream increases
the
effect
(through
of
the
cardiac
increased
adrenal medulla
output,
which
into the
parallels
sympathetic efferent stimulation
norepinephrine
directly
release)
to the
sino
atrial node.
System
response
time:
Circulating
epinephrine
requires
time to
tissue through the
systemic circulation
cardiac response.
The
norepinephrine
reach
before effecting
sympathetic neural
release) is
cardiac
a
impulse (via
received and processed almost
immediately.
Cascade-effects:
Vasoconstriction in the
serve
heat)
may
alter arterial
invoke the baroreceptor
System Behaviour.
static perturbations
is useful
may vary
in quantifying
time constants,
The time
required
while slow
reacting
A 'speed
blood
systems
response'
of
times. Fast reacting
systems will
circulation
(to
pressure which
con
may
response.
for the body's
substantially.
such response
cutaneous
to
respond
index (time constant)
systems will
have large
valued
to homeo-
have
time
small valued
constants.
INTRODUCTION
1
If
a stable
is
system11
system will react
new
18
according to its
the time
required
between the initial level
value
=
Initial + 0.632(Final
If
is
a stable system
-
system
This is important
impulses,
If
is
basically
quency to
function
oxygen
the
of
and
modulated^2
periodic
in the length
During
of
pulse, the
reach
62.3%
the
of
change
r when
=
Level
metabolic
to their
such as
the
may be
cardiac cycle
activity, many
within
This
this band.
transmits
neural
of system.
in nature,
the
some critical value.
a system which
system,
respond with
only
to frequencies
responds
type
system will
is below
pulses
only
autonomic nervous
rhythm rates return
of
the
cardiac
of
the
to
expected
physiologic rhythms
demands
rhythm, is
body but
per
compensate
increase in fre
upon cessation of
previous state.
one
and
upon
processing
autonomic nervous system.
change affects
stable
is dependent
The transmission
concentration,
systems,
A
frequency
the increased
sino-atrial node.
11
the
cardiovascular system
activity.
the
to
first-
step-response of
Psuedo-Periodic Cardiovascular Variations
1.2.2
their
system
and settle at some
final level (i.e. time
elevated
a periodic
is band-limited
condition.
support
the activity,
the
is already
a small change
for the transient
by
perturbed
frequency
a
a system which
turbed,
its
since
the
and
for the
time
in the
r which exists
step-change, the
with a
say
Initial)).
sufficient amplitude when
implies that the
level,
nature within some amount of
constant
in
initial
an
level. For example, the time
order systems represents
The
from
perturbed
being
system
carbon-dioxide
cardiac
the
of cardiovascular
concentration,
activity through
being
renin-
denned
angiotensin
as
a system
regulate
information is
a major
Arterial blood pressure, total blood volume,
and pH
also
be
system which
possessing
poles
levels
nervous
autonomic
Cardiovascular activity may
the
to
autonomic nervous system
altered
are
monitored,
and
system stimulation
by
is involved
the
of
action of other
with
only in the left half
blood
of
the
volume
complex
S-plane.
12A frequency
the
modulated pulsed signal
amplitude or strength of
the
pulse.
transmits information
by
varying the
frequency
of
'pulses',
not
1
INTRODUCTION
19
regulation.
In maintaining
pathways, the
nomic
the
neural
impulses
the
to the
sent
sino-atrial node or
system.
The resulting
mechanism
having
and
many
cardiovascular
a reaction
by
the
indirectly by
distinct
own
in
about
question.
by
This
time. With this cycling
in
conduits, blood
communication
the
responsible subsystem.
The
is
characterized
the
of
by
effects on
The
results
serum
HRV but
itself,
in HRV. This
by
the
endocrine
venous
blood
pres
a change culminates
listed,
in
a quantitative
Response inhibition is
quantity.
an overabundance of
the quantity
quantity, low-high-low. ..etc.,
the cycling
comes
of
the
over
physical state of
pathways, regulating the activity
phenomenon, heart
of
rate
investigation.
current
Variability
work
is known
variations of
HRV is
a
the
as
heart
elapsed
result
of
rate
variability
time between
communicated
maintaining homeostasis. Changes in
catecholamines,
and
respiration
other physiologic events make
cyclic variation
to
measured
Heart Rate
while
stimulation of
mechanisms with each
the items just
of
quantification of one such cyclic
beat-to-beat
to the heart
blood pressure,
For any
the
through
Response to
occur.
vessels or neural
heartbeats (R-R interval duration).
perturbations
of
investigation in this
phenomena under
which
The
genesis of
Background
1.3
cycling
the quantity
of
the
variability, is the
a
directly
blood pressure,
arterial
a second subsystem which reacts
results
upon
described in Section 1.1.3
these feedback
to increase the
a subsystem
activity
auto
time.
response
appropriate subsystem.
through
'electrical'
catecholamines released
circulating
quantities, continuously
decrease normally induces
brought
are effected
systems
either
activity
cardiac performance reflects
its
other
All the
sinoatrial node.
Changes in blood chemistry, temperature,
sure,
which
various control mechanisms superimpose
to modulating
contribute
levels,
cardiovascular performance
in the intrathoracic
action perturbs venous
rate
important
pressure
as
have the
consecutive
physiological
body
orientation,
most
significant
contributions.
a result of respiration
blood return,
(HRV)
and
activity
through pulmonary
and
1
INTRODUCTION
aortic pressure
Postural
in heart
time is
affects
(standing
body
regions
to
up from
hypotension. Some
required
to
combat
in
a acceptable range
waveforms
the
and
have
revealed a close
performance
the
of
developed
of
its
stochastic methods
of
various studies
in
sympathetically
which restores
activity
blood
of
pressure
blood
electrocardiologic
of
heart
rate
blood
hypotension.
arterial
the heart
autonomic nervous system activity.
for the detection
change and
pressure
autonomic nervous system
After
system.
electrical
cluding:
[9],
have involved
a
HRV resulting from the interaction
nervous systems with
cats
body
by
occurrence of orthostatic
variations
this
sense
via
methods
non-invasive
Many
studies
the
and
variability
activity
have
analysis
spectral content.
Likewise,
pects
to
redirected
the
of
compensate, this is known
not
required
areas of
relationship between
to
did
due to pooling
drop
would
[1, 4], further investigations into arterial
into the
methods revealed a connection
also promotes a modification
blood flow is
Since the first
cardiovascular
developed, investigation
were
time is
[1].
cardiac cycle
position)
in lower
preventing the
documented in 1733 by Hales
the
mechanisms
Normally,
arterioles
of
in the head
pressure
amount of
it.
Related Experimental Work.
were
a supine
if homeostatic
stimulated vasoconstriction
pressure
the periodicity
Upon standing, blood
rate.
orthostatic
more
modulation,
changes
blood in lower
as
20
dogs
the
[17, 18],
of
and
rats
[3, 21],
humans
lambs [33]. Focal
of species
the
cardiovascular system.
[1, 2, 11, 26, 32],
rabbits
variety
to investigate
sympathetic
Various
species
and
various as
parasympathetic
have been
studied
in
[8, 10, 11, 12, 20, 23, 26, 28, 31, 35, 36],
points germane
to the
present
study
are
detailed below.
The literature
the
frequency
low-frequency
Hz
spectrum of
band
and greater
contains a
that there
reveals
large
and
the HRV
are at
least two dominant
waveform.
In
humans,
the
high-frequency band, located
Hz,
respectively.
that 0.15
frequency
In
normal
frequency
these bands
component which corresponds
are
approximately
subjects, the
bands
within
termed the
at
0.04-0.15
high-frequency
to respiratory
band
sinus arrhythmia
1
INTRODUCTION
(i.e. HRV
breaths
of
21
the respiration frequency). Normal
at
per minute
20-30 breaths
Respiratory
(0.25-0.28 Hz),
Rate Regulation.
from respiration,
nates
hence,
through
strated
controlled
several studies
breathing
tivity.
[1]
example
that
suggests
renin-angiotensin
of one
system
Orthostatic Loading.
lates to blood
for
pensate
perfusion
low-frequency
is disabled
in
will result
signif
been amply demon
phenomenon as
device) [10, 12, 26, 28, 31].
of autonomic
blockades has been done
autonomic modulation of cardiovascular ac
HRV activity (about 0.04
by
chemical
Hz)
increases
blockade in the dog.
(disabled)
for
by
increased
frequency
and
tems [28].
orthostatic
are
action
of another
when
This is
in
order
an
to
altered
in
the brain may
orthostatic
decreased
posture
to
veno-regulation
occur
resulting
gravitational effects
hypotension
and are com
parasympathetic efferent
and observed
com
heart
activity
fluctuations
rate
36].
modulated
load
and
and
pressure regulation re
Upon standing, these
positions results
sympathetic
arterio-
perfusion of
tissue ischemia.
band (below 0.15
A decrease
Without
effects, insufficient
Several investigations have
Low-
in
origi
activity
36].
the brain.
body
upright
[5, 12, 23, 26, 28, 31, 35,
load,
of
gravitational
during
pensated
[35].
activity
One important factor involved in blood
of consciousness and
incurred
This
Administration
compensating for the
system
respiration
metronome or similar
changes
a respiration rate
homeostasis.
maintain
in loss
(via
[1, 2, 3, 9, 11, 21, 26, 28, 33, 35,
Akselrod
the
to investigate
2-12 have
modulation of cardiovascular
cardiac rhythm.
Neurotransmitter Blockades.
in
Partial
15-17
a respiration rate of
pl077].
purposely altering
icant fluctuations in the basic
have
and normal children ages
(0.33-0.50 Hz) [24,
per minute
adults
of
by
both the
high
are mediated
Hz)
HRV
components are
sympathetic
frequency band (>
by
the
increased
by
and
parasympathetic
0.15
Hz)
parasympathetic
system
orthostatic
nervous
HRV fluctuations
sys
during
only [28]. The increased
1
INTRODUCTION
due to
vaso-regulation
of
the heart
Diseases
lating
rate
variability
[14, 15, 16, 17],
[4],
exercise periods
in
[4],
[20],
Other
and
disorders
and use of
[4],
and
36].
bio-feedback
specific
[23],
pediatric
[4, 5],
re
my
head trauma
methods on patients with re
loadings
patterns under various
in flight test
interest in
hypertension
such as
familial dysautonomia
components
pilots
have
also
been
during
performed
P178].
Cowan
following
after
[10]
the
shows
cardiac
a significant
to be
shown
indicated that 15 days
an
reduction
but later
arrest
bio-feedback training to
has been
the
control
indicator
after myocardial
hertz13
(eq.
is
in
autonomic cardiovascular regulation.
the 0.03
eq.
peak power
Hz
results
data
suggesting
[14, 15, 16]
low-frequency
in
are
disappeared
frequency,
Goldstein
reduces
peak
near zero
the direct
Hz)
levels
respiration
a
in
to
severe
0.08
the data
on page
25 for
Reductions in HRV
power
cardiac
again
arrest.
Baselli
low-frequency
normal control
[4]
peak
loops
later determined that
became the dominant
normal autonomic cardiovascular activity.
head trauma
pediatric patients
acquisition
and
and
HRV
an explanation of equivalent
hertz.
brain
that
power
and analysis
writing.
See Section 2.1
levels,
six months
Hz
immediately
normal
delays in the
eq.
of serum catecholamines and
result of
rate.
power
towards
large amplitude,
Investigations
a return
HRV
HRV,
impending
infarction,
and a peak at
power
increased
representative of
indicates that
HRV
low-frequency
of possible
0.03
equivalent
in
showed
at
13
low-frequency
have had
studies
[10]. Investigations into HRV
normal adults
in increased
results
[4, 5, 12, 23, 26, 28, 31, 35,
diseases
diabetes
quadriplegics
cent cardiac arrest
[22,
spectra
patterns of specific
infarction
ocardial
loading
orthostatic
Specific Conditions.
and
HRV
22
injury
significantly
pediatric
brain death
[15,
16]. These latter
methods
detailed in this
INTRODUCTION
1
Justification
1.4
This
has been
research
perimental
protocols
endotoxin-induced
to facilitate the
and
collection and analysis of
of
Primary
study
patients
in the
and
the
will support
bit is
percent of neurologic
of rabbits
for this
nature
cardiovascular collapse
during
consideration
14Septic
nents of
heart
shock
software package employed
of
this
rate
work
is
a
form
the circulatory
but
The
analysis
based
are
on
head trauma
are pediatric
(University
Rochester Medical
of
of pediatric
each patient served as
is two-fold in
for
power within specific
variability
injury. The study
work
[17,
18]. The
of septic
of
not examined
in the
circulatory
action of
known
function is
on
pressure
[24,
is
for,
neurotransmit
using
on previous
frequency
resulting from bacterial infection. It
in dangerously low blood
methods
Based
individuals
rab
rabbit
also assessed
present work.
has direct impact
shock
system and results
[17]. The
early detection
power are expected within specific
shock
patients
own control subject.
endotoxin-induced septic shock
septic shock
in HRV
head trauma
their
and
frequency
The New Zealand White
nature.
and establish non-invasive
of,
but that data is
certain changes
The
of application software
and respiration waveforms.
on autonomic modulation of cardiovascular
rabbit model
studies,
development
New York). The primary hypothesis involves the investigation
an established animal model
ter blockades
anorexia nervosa.
Children's Critical Care Center
here to study the
used
EKG
aspect
the hypothesis. In this study
The study
the
clinical
establishment of a correlation of
and
with
HRV
with
Rabbits
for the
subjects
Strong
levels
information found in the literature.
Humans
Center, Rochester,
bands
disorder,
In
head trauma,
pediatric
correlation of serum catecholamine
the eating
ex
applications.
clinical
potential
have included:
protocols
specifically designed for the
are
Use
6hocku,
with
develop
to
close collaboration with physicians
techniques
analysis
injury,
collective analytic
1.4.1
the
and
in
this thesis is primarily involved
Specifically,
methods
Research
conducted
septic
brain
during
power
of
to date employing these
vestigations
the
23
bands.
susceptible
attacks
pll27].
the
to
compo
1
INTRODUCTION
circulatory infections
of
the depressed
at
are also
means
their immune
elevated risk of
with
power spectra
of septic shock
Diagnostic
use as a
might
be,
physiologic
in EKG
yet
signals
or portable analysis unit.
often
accuracy
in
with
and
such
patients
because
surgery
patients
and abdominal
work
may lead to
effort
individuals.
and
being
result
of neurologic
of
considered at
injury,
heart
the heart
the
cardiovas
rate
variability
rate
variability
the Rochester Institute
in the development
industrial accidents,
use of such a portable unit.
capabilities and perhaps assist
specific patterns of
Real-time processing
may
non-invasive
Prognostic Tool
detected,
is currently
Severity
automobile
the
to be
change.
Technology. If successful, this
occurs
in
This
AIDS
and
are several conditions which alter autonomic modulation of
system, there
associated
Cardiac
systems.
circulatory infection.
for the early detection
Although there
cular
those receiving chemo-therapy
such as
state of
Potential
1.4.2
24
of a
hospital bedside
secondary to head trauma,
might
be
assessed
with
This may lead to improved
in assessing different treatment
of
modalities.
which
a certain
prognostic
2
METHODOLOGY
2
25
Methodology
This
section
for heart
details the data
rate
variability
collection and
data
formed
methods
and
described
supervised
mentioned analysis
of
brain injured
changes
Additional
have been
published
Early
a
The
brain dead
developed
Both
pediatric patients.
The
the
ultimately function.
one clinical and one
variability resulting from
rate
and
laboratory
studies
study involved heart
clinical
software package
software structure upon which
physician).
collaborating
(vS.l)
and employed
rate
study (per
utilized
the
afore
analysis
variability
trial investigated the
laboratory
endotoxin-induced
septic shock
in New
rabbits.
using the developed software,
studies
performed and
[14, 15, 16,
the preliminary
17]. Reproductions
results
of
the
from the two
separate
from
some of
these
studies
published abstracts of
this
discussed,
have been
related work
Methods Employed in Previous Experimental Work
computational methods enabled
variability
waveforms
derived from
gorithms enabled rapid
HRV
spectral
(FFT)
power
processing
frequency specific information
physiologic
of
determinations
the data
employed
methods and autoregressive methods.
complex
demodulation
diovascular
is
by
in
developed
included in Appendix C.
2.1
an
is the base
York)
were employed
package.
and
in heart
Zealand White
are
New
acquisition and analysis procedures were
The
The ASYST
acquisition and analysis.
(Keithley-ASYST, Rochester,
algorithms
processing
FFT
events of
and appears
very
analysis approach
adopted
here.
short
to be
data,
and
by
[5]. There
in the
to be
the late 1960s
are
two
duration. Much
for
from
computer al
preferred methods of
literature, fast Fourier
A third method, described
useful
extracted
transform
by Shin [32]
is
spectral analysis of autonomic car
work reported
in the literature
employs
[2, 3, 8, 9, 11, 12, 14, 15, 16, 17, 21, 23, 31, 33, 35, 36],
which
2
METHODOLOGY
26
(in
AUt
*
I
T?
ftl.\.
n'\
I M
*
T<
I
1
R-R(I>
'l
h
^v
Figure 5: An
series or
event series
representing R
some original
rate.
an
of
is
EKG
most
Computing
signal
(Figure
determined15
the
elapsed
shown
recognized
duration
values
re-sampled at
signal
[4]
using
a
if the
i,
to
process of
is
signal
adjacent
detecting QRS-complexes from
series, the time
sampled
R-wave
using
peaks
in Figure 5-b [4].
as an
irregularly
plotted versus
linear,
cubic
spline,
or
a constant
sampling
values as a
The interval
time. This interval
for
to
function
function,
sampled waveform of
yield equi-time-spaced samples
R-
between
immediately leads
R-R interval duration
as shown
considered
rate
a constant
interval
function may be
subsequent
digital
backward step function interpolation
[32].
Direct processing
15Given
interpolation (c). (Reproduced
produce an event
which contains
from the tachogram,
processing
method
be
can
to
times between
R-wave event,
in Figure 5-c,
In the
5-a)
easily
interval tachogram dataset
the
obtained via
1987)
Fast Fourier Transform Methods.
wave peaks
in the EKG (a). R-R interval duration
peaks
tachogram (b). Interval function
from Baselli
ft
1,
R-R(t)
an
toT,T,/2.
by
EKG sampling
the FFT
period of
algorithm
T,(T,
=
1//,),
on
both the interval tachogram
the accuracy in
locating
an
R-wave
peak
and
the
is limited
2
METHODOLOGY
re-sampled
produced
(heart)
hertz
interval function have been
from the interval tachogram
beat (c/b). The
if R-R variability
A
power spectrum produced
rally to the FFT
spectrum
is
troduced
by
small
process
expressed
by
frequency
be transformed
by linear
by dividing
by
directly
rate used
in the
as a
c/b
is
the
power spectrum
expressed as
scaling into
cycles per
an equivalent
R-R interval
mean
much smaller
statistical
analysis
behaviour,
of
than the
without
interval
mean
the regularly time-spaced
function
datasets.
The
Along
and
the dataset.
modelling
methods
is that
a
advantage
is that identification
of specific
method and
Preparation
Strong
of
regularly
autoregressive
with
variance
cross-correlation
within
Human Subjects.
An
the interval function
approach
of a preprogrammed
sampled
frequencies [4].
is
The human
before
being
mean
datasets
as
approach
involves
measures
of sam
information
reveal
employing the
of
autoregressive
not a requirement and another
straightforward and will not
Low-frequency
has been documented
Study
of
dataset is
of random noise
modelling
and
advantage of
components can
[4, 5, 10, 20,
interfere
be detected
26].
Subjects
subjects
were pediatric
Children's Pediatric Critical Care Center. All
gave written consent
produce
in
error
software used.
patterns
2.2
(hertz). The
of cycles per second
natu
The resulting
samples.
is primarily due to the availability
repeating
easily using this
interval function lends itself
for the re-sampling is sufficiently large [4]. This is the
auto-correlation
identification
re-sampled
the interval tachogram to
of
present work and
in the
algorithm
from the
Autoregressive Model Methods.
with
in the
results
(variance)
virtue of
the interpolation
if the
employed
ple
in the literature. A
performed
[4].
value
FFT
c/b scale can
may be accomplished
scale and
appreciable errors
is
27
studied under
the
brain
injury
patients
clinical subjects or
at
the
their families
supervision of a research physician.
2
METHODOLOGY
28
The study included 20 patients, 9 brain dead
than
Individuals
catecholamine
strumentation,
ous
blood
the
throughout
To
Exclusion
the
or
of one
signals
Cold
of
evidence
atropine,
of
and
in these
17The
or
of
patients
15 indicates
less is indicative
cold pressor
in the blood
less
testing
minutes
test
was accomplished
but data
within
healthy
pressure and pulse
rate,
intact
the
arterial
some
patients)
analyzed encompassed
only
physiological state
previous
inhibitors
24
electrocardio
(theophylline,
hours;
mcg/kg/min).
8 A.M.
to the myocardium;
injury
or,
amrinone),
moderate-dose exoge
Since dopamine interfered
serum
catecholamines
were
spectral analysis were collected.
recording, the
response,
a
GCS
carotid
of
neural reflex
which are regulated
pathway
by
the
and
3 is the
is
to
artery
in individuals
of a comatose condition and severe neurologic
relies on an
(on
cardiopulmonary arrest;
a measure of responsiveness
a normal
was used as
indwelling
rabbits were anesthetized prior
pressure
independent in
was always recorded at
anoxic/ischemic
but data for
blood
for
patients required mechanical
assay measurements,
The
electrodes
catecholamines were obtained after collection
prolonged
the
serum
purposes of continu
due to the normally changing
severe
epinephrine
continuous-time
function. A GCS
7
transducers for the
phosphodiesterase
,cThe Glascow Coma Scale (GCS) is
score
for 4
From existing
data (from the instrumentation). All
New Zealand White Rabbits.
A
pressure
infusions (dopamine > 10
norepinephrine
For
to
immersion. Serum
recent
Surface
test'7.
pressor
acquisition.
pressor
ice- water
antagonists
nous catecholamine
ration.
cold
bedside monitoring equipment,
for data
was affixed
included
criteria
administration
not measured
a
twenty-four hour period, human data
beta-adrenergic
with
Scale16
respiratory parameters,
respiration were employed since
normal
reduce potential errors
enzymatic
or
to
response
from the
hand in
seconds of
a
Glascow Coma
with
electrocardiogram and
impedance
and
tubing
physiological
ventilation.
graphic
a
pressure monitoring.
the last 128
of all
and
separate
pressure
immersion
by
levels,
the physiological
catheters,
for
were analyzed
lead II EKG
source of
11
to 6.
or equal
standard
and
was cannulated
with neurologic
dys
smallest possible value.
injury [24,
used
aseptic prepa
to
p551].
stimulate an
autonomic nervous system.
increase
2
METHODOLOGY
with a pressure
the
of
tube
29
which was connected
for
rabbit was shaved
Collection
The
human
EKG
of
data recording
same
and
rabbit
application of surface electrodes
(from the
procedures
The analog
studies.
systemic
pressure signals were
recorded,
priate monitors
continuous-time
depending
tranducers. The
78205D in
physiologic
data
acquisition card and
to-digital
of
which
ranged
mately 4.9
data
from
module
rate
include lead II
78213C
78212D,
and
and central venous
experiment, using
conjunction with pressure
signals were recorded
a
Hewlett-
tubing
from the
DT-707 terminal board. The
DC resulting in
a
a
12-bit
resolution
voltage
No in-line anti-aliasing filters
and
appro
Data
analog-
(4096 values)
resolution
of approxi
were employed prior
semi-simultaneously18
but
the
are recorded at
a
factor
of
a
high sampling
respiration and
same rate
blood
to
can
acquisitions are sequential
equivalent
to 1000 Hz.
for
only
access
each
in this
a single
'sample'
do
to
hertz
1000
proper resolution
reduces
the
high
Post-processing
effective
investigate the
of
sampling
recorded
blood
work.
channel
time-period.
rate of
not require such a
maintain synchronization.
studies will
the hardware
sampling
pressure signals
16 to 62.5 Hz. Subsequent
filtering
a
is necessary for
decimation
digital
pressure waveforms and are not analyzed
18Since
rate
and
respiration signal via
by
using
Although
.
the EKG signal, the
the
volts
specific
used
signals were recorded
or samples-per-second
rate
the DT-2801-A
per quanta.
millivolts
collected
collection.
All
of
to +10
-10
data
personal computer equipped with a
Translation DT-2801-A data
conversion
and respi
for both the
were used
monitors models
the
upon
AST Premium 386/25
an
using
chest
of rabbit preparation.
blood pressure, intra-cranial pressure,
pressure monitor model
external pressure
for lead II EKG
instrumentation)
using Hewlett-Packard
Arterial
Packard blood
transducer. The
Physiologic Data
and respiration signals
respectively.
an external pressure
See Appendix B for further details
ration signal monitoring.
2.3
to
at
Each
any
one
channel's
moment, the
data
actual
represents a
N-channel
time sampling
2
METHODOLOGY
30
For the human patients,
3
from the instrumentation.
from
recording
pressor
Glascow Coma Scale
patients with
samples
cold
indwelling
Serum
arterial
and were analyzed
< 6
was
performed on
6 brain dead
immediately following physiologic
standard
at
the
completion of
laboratory
data
the
techniques
of
blood
continuous-time
not
and
collection
collected, in the form
catecholamines were
catheters,
by
testing
data
described here (see
Appendix B).
Analysis
2.4
After
collection
cessing
of
stages are
Physiologic Data
of
the
physiological
necessary
prior
interpretation. The processing
Detection
of potential
Recording
of elapsed
Transformation
beats
per
of
a
computer
disk
file,
extraction of pertinent spectral
involving
stages
QRS
the EKG
waveform
complexes and verification of
time between
verified peaks
the tachogram to
an
to form
variability
record
filtering
Computation
of
Calculation the
information
pro
and
its
include:
R-wave peaks;
an
instantaneous heart
interval tachogram;
rate record
of
the instantaneous heart
rate record
in
units of
Extraction
of
'windowing'
of
and
the heart
the Fourier transform
power spectral
the
stages
into
a
heart
rate
containing 4096 points;
density
of
of
rate
variability record;
the heart
rate
variability record;
the Fourier transformed heart
ability record; and,
The processing
data
several
minute;
Expansion/interpolation
Digital
to
to
signals
signal power within specific
involving
the
frequency bands.
respiration waveform
include:
rate vari
2
METHODOLOGY
Digital
filtering
Decimation to
Extraction
31
of
the respiration
extract
and
16"1
every
dataset;
the filtered
point of
computation of the
respiration
Fourier transform for
a
64
dataset;
second segment
of
the respiration waveform;
and,
Calculation the
The literature describes
and
for evaluating the
sections
Note that the
is
restricted
is
performed
processing
appear
Detection
Several
approaches of
diogram
(EKG)
ASYST
software
present
of
directly
below.
'scan-window'
The
employed,
select
and arranged
(arrays),
EKG
19The QRS
complex
steps
waveform
the
[6, 4]
complexes
[4]. The
involved in the data
following
processing.
continuous-time physiological signal analysis
original waveform.
The
analysis of
the
respi
Specific topics relating to
the R-wave
a
in
peak
Due to the
each
QRS
complex19
of electrocar
analysis capabilities of
the PC-based
blocked- window or array-based approach was used.
the QRS
in the
complex
candidate
conversion and peak
detection
method
R-wave peaks; the
detection
developed
candidate
peaks
The
algorithms
uses a
are
fixed
dis
size
investigated
validity.
waveform
in the file
this file is
the
QRS
in Appendix A.
detecting
Further,
original
the HRV
of
record.
QRS-Complexes
of
further to verify their
for the detection
unless otherwise specified.
signals were considered.
to
tense,
analog
on
are always processed as arrays
cussed
within
in
discussion
following
2.4.1
data
and
to the EKG waveform,
ration signal
signal
various approaches
power spectral content of
in detail
describe,
density of the Fourier transformed respiration
power spectral
as subfiles or
referred
bears
data
to
as
actual
in
a
two-dimensional
data file using
constructs
the integer data file. Each
a unique shape
the QRS complex, is the
are stored
item
that is
being
useful
in
searched
integer format
a row-column
form
column of a subfile represents
detecting
for.
in
an
its location but the R-wave peak,
2
METHODOLOGY
a specific channel
channel.
The
32
from the data
(channels)
number of columns
subfile represents a sampled point
fixed
1024
at
of
1000
Hz,
in the integer data file is
the sampling
period
actual
total
of
each recorded
row of a
of a subfile
rows)
(see Section 4.1.1). The
Because
subfiles.
for any
one
of
total
the sampling
rate
regardless of
a nominal
(i.e. 262144
seconds
is
therefore dependant
channel,
information for
above
for
5. Each
and
operator selectable and
time is approximately 262
recorded
between 2
constraints
one millisecond
Given the
number of channels recorded.
the
is
one column
in time. The length (number
acquisition, but is nominally 256
on each specific
board,
range
may
due to hardware
rows per subfile
number of subfiles
terminal
acquisition
the
recording20,
sampled points
per channel).
The first
stage
data into
acquisition
voltages requires
to their
that
to
of
the
processing
real-
valued
use of a
during
was used
data
file,
the
the
or
'length'
128
each subfile
is
in
size.
subdivided
Nominally, they
analyze.
Figure 6 illustrates the
processing
the
of
nominal
are
performed.
'blocks'
data
20A
rate of occurrence
point
for
possible
represents one millisecond
nominal
recording is done
at
total
the
The
original
integer data
raw
same resolution scale
is then
stored
and analysis.
Since
number of scan-windows.
used are
in
size
producing 4
,
number of
1,024
'blocks'
of
various
the
number of
512, 256,
usually
windows per
scan-
windows
data in
points
in
which
each
to
the
'block'
contained within each stage are also shown.
The reasoning behind selecting the
from the
a
the
the
of
peaks and reduce occurrences of
integer
points
relative scale of
the EKG dataset is
number of smaller
are
the
processing
scan-windows
256
scale
the integer
of
converted voltage signal
R-wave
an
to
utilizes
subsequent
all
conversion
of restoration
algorithm
The
into
recording, there
For
a
file, for
detecting
process
algorithm
is 1024 points, the
of each subfile
points
of
subfile.
and
This
original acquisition.
To increase the probability
'false peaks',
The
linear interpolation
real voltage
is the
collection
voltages.
representative voltage values.
another
the
data
after
nominal scan-window
QRS
complexes
of elapsed
1000 hertz for 256
in human
time, the
subfiles with
size as
256
patients.
scan-window
1,024
points evolves
Since
is 256
each
millisec-
samples/channel/subfile.
2
METHODOLOGY
33
II-
I
I-
EKG WAVEFORM:
262,144 Points
256 Subfiles
SUBFILE:
1,024 Points
4 Scan- Windows
SCAN-WINDOW:
256 Points
1 Zoom- Window
ZOOM-WINDOW:
95 Points
1 QRS-Complex
R-Wave Peak
Figure 6: A Comparison
of
the EKG
to the
waveform stage
the
relative sizes of
the data processing
zoom-window stage.
'blocks'
used
from
2
METHODOLOGY
'wide'.
onds
the
For
minimum
to
correlates
34
a maximum of
duration between
riT11./r
BPMmax=
this
Using
is
acceptable.
signals with
excessively
/60sec\
\ 0.256 sec/
\ mm
The
real voltage
the
careful
By
operator.
threshold
value can
detection
procedure
The
to
be
found
relate
The
selected.
faster heart
of
elapsed
of
time
each
termined
to the
the EKG
values
scan-
which
of
voltage
the QRS
current
later
during
window
is
peak, if
value
by
occurring 'too
a potential
at
this
per minute
(BPM)
as
If this
is
not
complex
in
some
operator selectable
of
to
the
scan-
for
account
rates.
this point,
signal
seconds of
prior
is
signal
complex
is
viewed
data,
graphically
a proper voltage
to implementation
of
value
the QRS
several
global values are
using
the
in
all peaks
variables
are used
each scan-window
then easily
and refers
elapsed
a sort and
indexing
scan-window with
to,
converted
a previous
the largest
to the
most
recently
to the
into
real
index is de
amplitude.
This
is then tested for
verified
QRS
com
immediately discarded
next scan-window.
candidate peak
an
the temporal proximity threshold
R-wave peak, it is
the
procedure,
a candidate peak which
time)
continues with
violated, this
Since
procedure.
bookkeeping
peaks
candidate peak violates
to
processed one scan-window at a
detection
the detected
close'
peak, processing
stage
BPM.
processing.
element of
the location of,
one exists.
of
These
processed
temporal proximity (closeness in
plex
This
milliseconds.
threshold value, temporal threshold
scan-window,
times)
recording.
locates the
represents
is
the first 20
file containing the EKG
implementation
relative
QRS
file containing the EKG
scrutiny
the indexes (elapsed
beginning
index
scan-window,
discussed below.
real voltage
during
As
a
/
scan-window size
and all other search parameters are set at
are
234 beats
=234
r-1
absence of a
slower or
At this stage, the
time
rate of
/ 1 beat \
in the
scheme results
which
windows,
by
be less than 256
complexes cannot
instantaneous heart
an maximum
in
complex occurrence
here:
shown
EKG
QRS
one
only
is further
as
If temporal proximity
processed
for validity
by
use
METHODOLOGY
2
of a
'zoom-
35
windowing'
algorithm.
The temporal proximity threshold
is
value
operator
selectable.
Zoom- Windowing.
to verify the
T-waves that
set.
of
The
the
Figure 7
is
QRS
and
the
By
a
valid
about
'centering'
as
the test
specified
a
QRS
complex
to be detected
In the
figure,
entire
at
that
point
L
marks
milliseconds
candidate peak
that
was
is
large
[7,
The
p422].
found
properly
the
within
during
the detected peak, only
range
zoom-
the
scan-
QRS
actual
shape and voltage characteristics which
the identification
by
which
of
actual
with an example of
search parameters are not
60 to 100
area about
the probability
reduce
being interpreted as
from
is 95 milliseconds,
of
employed
criteria
employed, namely
an
EKG tracing.
the Q-R
a scan-window
or
edge,
either
R-S intervals, causing
Figure 8 illustrates
the
(Courtesy
of
the
Strong
Chil
York)
EKG record,
edge.
to
is
proximity.
New
either
along
scan-window and
EKG trace
if the
the necessary
large T-waves in
Throughout the
errors
the
Figure 7: Example
Hospital, Rochester,
conducted
a representative
temporal
dren's
This is
excursion T- waves
voltage excursion and
of
than the
duration time
formed
peak
smaller
zoom-window
complex occurrences will possess
discriminate
large
shows
complex
centered and
window algorithm.
complex.
introduce detection
might
nominal size of
normal
window
QRS
fluctuations
complexes.
is
zoom-window
presence of a
spurious voltage
QRS
A
examples
occurrence of a slice
of
left
a
this
or
false
right,
may
slice
candidate peak
'slicing'
phenomena.
along the R-S interval
by
a
scan-
2
METHODOLOGY
left edge; this
window's
construction of
the
a subsequent
'slicing'
this
by
the
edge of
points
the detected
cases where
number of
data
points
by
95
zoom-window, the
from the left
zoom-window, the
It is
peak
noted
(i.e.
points
is
attempt
made at
of a
timing-error
effect
After
the
voltage
and
excursion
compared
to
fully
the
is
edge
at
25
of
the
within
in
number
subsequent
'last'
peak
the
right
few
a
of a
QRS
a
record.
72, for
total
of
a
95
peak
is kept
for the
processing
of
as
this
is illustrated in
For
a nominal
72
at
fully
points
populated
points.
be
an actual
a valid
potential
the data
or
to include
By design,
be located
points,
(i.e. first
window edge
phenomena
would
adjust
no
peak,
invalid
peak.
eliminates
any
may impart.
zoom-window
zoom-window
excursion
record edge
into EKG
Although the
and/or
the
voltage
is indicative
the
peak, the true peak,
zoom-window.
This
window
was, to find the index location
excursion
of
peak when
point at
a record edge scan-window might not
with a operator selectable
large
R-wave
actual
data
to the right to include
in
formation,
the
points
the processing to
window
'first'
populate
insufficient
an
shifted
stage of
and
a
'valid'
as a
candidate peak.
R in Figure 8).
this
possesses
If the
right
Since
edge.
Hanning
alignment
scan-window
or
the
away from that
shifted
detected
a verified peak
L
Application
complex
window
that
is
zoom-window
Figure 9
(25+47)
of
peak occurs near a
incorporates the
the QRS
in the inclusion
case results
R in Figure 8. If the
is kept
R)
occurrence of a slice
addition of an adjacent scan-window
detection
at point
before
be detected.
would not
shifted zoom-window
point
(point
scan-window shown
last scan-window), the
a sufficient
window allows
the
marks
right edge; this
to 'zooming'. The
This is illustrated
occurs.
later,
In those
zoom-
of a previous scan-window
Point R in Figure 8
a scan-window's
scan-window prior
to establishing the
in the inclusion
case results
zoom-window.
along the Q-R interval
prior
36
of
is then
its largest
sorted
value.
due the depolarization
of
the
as
maximum
is
computed
complex
inherently
complex
A QRS
indexed,
The
member.
containing the QRS
threshold
and
myocardium.
This
user-selected
value,
complex.
voltage excursion within
the
zoom-window
is less than the
2
METHODOLOGY
Figure 8: A QRS
edge slice of
37
complex sliced
the Q-R interval
by
a scan-window edge.
and point
R
Point L
marks a
left
marks a right window edge slice of
window
the R-S
interval.
Adjustment for 95-Point
R-wave Peak
at 25 Points
Figure 9:
A QRS
Zoom-window
Zoom- Window
"
complex
adjustment
detected
to include 95
near
the
points
is
'left'
edge
necessary.
of
the first
scan-window.
2
METHODOLOGY
the candidate
the
a
38
is discarded
peak
maximum voltage excursion
and
in the
final temporal proximity test is
temporal proximity is
peak counter
is incremented.
continues with
the
here,
the
index (index
global
Otherwise,
using the
same
candidate
R-wave
referenced
the
detection
during
verified
R-wave
temporal proximity
of slow
Zoom-
candidate peak
all
the
scan-
peaks
verification
When
analysis
during
candidate
zooming
complete.
entire
EKG
262144]. The
transforming
21This is
the
name
is
the
a
window.
If
the threshold value,
value as
is
before. If
promoted
record
is discarded
during
start)
and
to
valid
and
the
processing
peak
redundant, there
(using
scan-window),
proximity.
scan-window peak
each scan-window except
for
zoom-windows
this array to
a
the
are
actual syntax used
detection
violation).
phase
has
However,
due to the
validated
complex
detection
post-
millisecond
sampling
period
R-R interval duration
(without curly
placeholder and enhances
braces)
to the
appear as:
becomes
the
the indices
start of
the
[3, 900, 1923,
obvious
here in
values.
in the developed
identification
phase of
contains
peaks with respect
{Peak. Indexes} dataset may
represent
The fact that
above.
the detected R-wave
For example,
voltage-
when a candidate peak
(for temporal proximity
have been processed, the QRS
of
cir
'wide'
a
detection phase, that the
temporal
are
validation.
window stage
usefulness of
necessary
signals
violate
the
seems
Indexes}21
The resulting array, termed {Peak.
specify the location
record.
for
tests described
which
...,
actually
detected in the
all scan-windows
is
peak will
occurs once
rate
the secondary
was not violated
windowing
is discarded
not
heart
in the immediate decision for
bearing
no
peak
scan-
next scan-window.
after zoom-window alignment and
threshold
next
threshold
to the EKG
Although this secondary temporal proximity test
cumstances
the
continues with
zoom-window meets or exceeds
performed
not violated
recording its
by
status
processing
program.
of variable names.
The
period within
2
METHODOLOGY
Creation
2.4.2
The
of
construction of
the HRV Signal from R-wave Peak Location Data
the HRV
several steps outlined
of
array
by
dataset
of elapsed
(N
beat. The
1)
mean
actual
the
times between
peaks can
2,
is
rate period
steps are
be
constructed
number of
intertwined because
equivalent
to the
from the {Peak. Indexes}
detected
interval tachogram
points represents an
heart
index locations array involves
software used.
N is the
where
peak
program, many
capabilities of
evaluating Equation
of
from the R-wave
signal
below. In the
the array processing
An array
39
and
peaks.
has
The resulting
units of seconds per
this interval tachogram
mean of
array.
PI{k
Tachogram(fc)
If this tachogram array is
beats
per minute.
PI{k)
(k
,
to
converted
termed the instantaneous heart
units of
+^q~
=
This
is the time-averaged quantity
rate
{IHR.
beat
Values}
Values}
After
rate
The
and
seen
R-wave
IHR Patching.
Figure 10 displays
at points
for this EKG
A
9
and
the heart
B
subjects,
further processing to
some of
exclude
the
which
has
heart
rate
were caused
shape and
the detected
peaks
spurious peaks
variation
an example
rate about
waveform was about
these
dataset
by
1.5
the
in heart
{IHR.
mean
anomalous
R-wave
Values}
heart
rate.
fluctuations
peaks.
The
volts.
strength of
might not
is
(3)
1,2,..., N-l)
=
volts and were selected as
Due to the variability in the
from different study
peaks and
scrutinized.
waveform of about
maximum
(k
visual representation of
steps,
mean
a
dataset.
ttt,
periodic variation of
in the figure
EKG
be
inverted,
be formed
Tachogram()
1)
above
available and can
original
normal
the two
illustrates the
'glitches'
in the
Tachogram (k +
completion
becomes
dataset
-
=
can
(2)
N-l)
...,
then
and
60
IHR(*)
1, 2,
is indicated in Equation 3. The
{IHR.
the
or
array
process
of
minutes per
=
the EKG
be
actual
signal
R-wave
sometimes necessary.
This
2
METHODOLOGY
stage
processing
as
any occur,
to
remove
40
involves
visual
of
{IHR.
in Figure 10, {Peak.
Indexes} is
the
points
reconstructed.
contributing to the
Recall that
R-wave (i.e. contributing)
Figure 10: Example
glitches at points
lee.
inspection
A
peak
indices
B
are
the
spurious
Values}
for
by
interval
and represents one
of computer processed
and
processed
in {IHR.
each element
Values}
the IHR.Patch
value
and
{IHR.
If
procedure
Values}
is derived from two
is
adjacent
R-R interval.
instantaneous heart
result of glitches
spurious occurrences.
in the EKG
rate
(IHR)
dataset. The
signal.
-i-
x0
80. a
60.0
--
a
40.0
--
ee
s
20. 0
.
--
000
'
'
"*
.000
16*. 0
321. 0
TIME
Figure 11:
Example
IHR.Patch
algorithm.
of
computer
'
481. 0
641. 0
<s#o)
processed
'
801. 0
xEB
IHR dataset
after
application
of
the
2
METHODOLOGY
Baselli
41
indicate that R-R variability is
[5]
normal sinus rhythm.
The
20%
value
rate,
the
of
not
median
the
mean
heart
does. This is done to
selecting the
the
to adequately
this type
eliminate
'remove'
of
'salt
filter to
ber
the
intervals,
M,
(2fe,
in value,
causes a
rate
for
varies
variability
to
produce
some positive
and pepper
function
high
degradation
noise
are
while
expected,
value appears
corruption.
Note that
process
IHR.Patch is
and
operator
in Figure 10
shown
Baselli
by
the
and
the
Such
method
an approach
in
a
stage
Fourier
the
on
is
A:)
not
of event number
grey
or
low,
of
the image
about
the
digital
current
clarity.
is
analogous
to
use of
removal
involves the fast Fourier transform
Values}.
subject
a
of
time
of
frequency (in
a power-of-two num
and since
studied, M
function
problems exist with
function
Second,
is necessary
the
number of
will not
at
R-R
necessarily be
this data processing
(R-R interval).
image,
grey
Three
coefficients as a
by the utilization
scale
may include the
signals22.
integer
depending
widely
problems are resolved
either
'patching'
dataset, {HRV.
Third, {IHR. Values}
a
Values}
automated
by
as
from {Peak. Indexes}
method requires equi-time-spaced samples.
but rather,
22Salt
dataset
removal of six points
an alternative
from digital
algorithm
a power-of-two.
All three
blind,
value used
Values}
An upcoming processing
the heart
First,
in the
data
heart
median
in the dataset
The 20% tolerance
via a
is nominally
determination
in {IHR.
rate of
dataset is illustrated in Figure 11.
noise
of points
stage
resulted
pepper'
using the FFT
Hz).
{IHR.
original
remove anomalous values.
and
of
points
the
implemented,
not
data
heart
mean
the
uses
spurious values
mean.
The tolerance
Values}
HRV Dataset.
(FFT)
to the
valid peaks.
Processing
resulting {IHR.
median
criteria
spurious values
equivalent
removes
processing
IHR.Patch algorithm,
a
influences from any
Since few
procedure
for
the
of
point exclusion
remove spurious occurrences without extensive
therefore may
Although
This
rate as a reference value
effectively be
of error
selectable.
{IHR. Values}.
of
10%
order of
for contributing
criteria utilized
reference value.
median will
the
on
of an
say,
can
scale values
interpolation
be
in
algorithm
to
yield
'spikes'
represented
a region of
as anomalous
the image. This
'noise'
2
METHODOLOGY
another
with a
array
in
real
to
control
time
samples.
42
fixed length
4096
of
The
points.
described in Section 2.1. The interpolation
as
the time spacing
that
such
each new
Linear interpolation between
approach was considered
'times'
but expediency for
a
non-linear
{Peak. Indexes}
method uses
array index
represents equi-time-spaced
in {Peak. Indexes} is
working
is
algorithm employed
used.
A
cubic spline
prototype program precluded
this
option.
The
dataset
which produces a
but is
ations
processing begin
actual
interpolation
{HRV.
beats
algorithm
per
Values}
on page
subtracting the
temporary dataset
beats
centered about zero
which always contains
units of
by
is
described
4096
minute,
In the
{HRV. Values},
from the {Peak. Indexes}
same magnitude of vari
This dataset is
in the heart
processed with
the necessary form for FFT
the
variability dataset
rate
This resulting dataset is termed {HRV.
points.
Values}, has
analysis.
Note that
to the interpolated interval function discussed in Section 2.1
(4096
pts/262 sec).
{HRV.
original
Values}
extracted
fewer
points
EKG
the HRV Dataset
is
digitally
of about
2 Hz. The
1000 hertz).
cardiac
15.6 hertz
sampled
above
use of
and
dataset,
frequency
the
=
describe
(4096)
filtered
from the HRV
with
rate
were recorded
points
HRV
In the
activity
results
frequency
is
process
over
for the
to
the
unrelated
of
same
reduced
represent
creating
duration.
HRV dataset
to the sampling
waveform.
of spectral content contained
nents above
of
sample
Note that this
uses an effective cutoff
context
(i.e.
HRV frequency
a sampled
the
seconds
much
Thus,
only in
rate
the
contains
EKG acquisition, nominally 262,144
approximately 262
tion is
result
heart
25.
original
rate of
to
above
Power Spectral Analysis
2.4.3
that
per minute.
and represents
equivalent
mean
of
a
then 'windowed'. Before the
Blackman smoothing filter is
5 Hz. The meaning
described
sampled
in HRV datasets
the 5 Hz
spectral
cutoff
of
this
cutoff
HRV frequency.
frequency
mainly
employed which
frequency
Early
revealed no significant
informa
the
valid
investigation
frequency
smooths
is
compo
'sharp
edges'
2
METHODOLOGY
43
resulting from
use of a
eliminates
noise present.
window
is
any
the
and
and
rather
To
to the HRV
applied
The filtered
linear
'windowed'
HRV
variability in the
converted23
ranging in
to
a single-sided
frequency
magnitudes
component
equal
have
units of
of
The
in {PSD. Array} is
of particular
frequency
interest located
band
total
and
power
bands
range of each
'For
and
example,
The
length
4096
of
a nominal
resolution,
262.144
(A/),
Finally,
points
information
current
study only
of
and
>
0.15
respectively.
deemed
operator selectable.
the heart
The
by
represented
discrete
and
a
frequency
line
or
bin
the Fourier
of
performed.
Hertz.
the heart
rate
variability
band-specific
powers
two
frequency bands
and are
termed the low-
are
power contained
displayed in
The
report
bands
to
one sided spectrums.
hertz
in
each
form. Other
number of
approximately 0.0038
in these
component
computations required
two to
dataset
frequency
of each
frequency
necessary.
conversion of
second record yields
Hz,
Total
the largest
/
when
previously, there
amplitude of
details in
is
conversion
BPM2
0.01-0.15 Hz
4096
of
point
density dataset, {PSD. Array}, is
powers are computed and
mathematical
HRV
element
are expressed as
when
dataset
a
2049
a
contributions of a
time24.
mentioned
be investigated
in
sampled
Each dataset
spectral content
As
at
to one-half the
frequency
to the
in
results
conversion results
indicates
record
density
useful
frequency-band is
23See Appendix A for
2
Hanning
a
(see Appendix A).
process
a
also
The Fourier transformed HRV dataset is
per minute.
line'
spectrum,
the band
can
hertz)
high-frequency band,
in the
and ratios of
frequency
the
The
power spectral
and power ratios are evaluated.
band,
leakage effects,
has
but
algorithm
magnitude and phase spectrum of
waveform.
the total
power spectral
Band-Specific Powers.
contained
beats
'spectral
to the inverse
the
two-sided
spectrum.
in {Smoothed. HRV}.
units of
bands,
the smoothing
the FFT algorithm
with
from DC (zero
transformed dataset into the
The
after
dataset, {Smoothed. HRV}
EKG
original
magnitude and a phase
is
interpolation
element values represent equi-time-spaced samples.
complex values which represents a
the
cubic spline
minimize potential spectral
dataset
Processing {Smoothed. HRV}
rate
than
spacing.
and
obtain
2
METHODOLOGY
band-specific
these
The
the
power
powers and ratios
contained
power spectral
frequency bin,
indicating
44
within
densities
A/. This is
the lower
a
is the final
specific
frequency
that band
over
expressed
stage of
and
in Equation 4
edge of a particular
band
the data
band is
processing.
then multiplying
itow is
where
ihigh is
and
from summing
obtained
by
the
the index
the index
of
of
the
width of
the
{PSD. Array}
upper edge of
the band.
('high
\
J2 {PSD.Array}(n)
Data processing
required
to
variability in the originally
2.4.4
second
a composite
segment
algorithm
The decimation
This
partial
unnecessary
5 Hz
and
procedure
record
original
provides
computational
is included in the
those
peaks
The
to FFT
analysis
simultaneously
filtering
point
frequency
complexity.
prior
digital
16t/,
every
sufficient
Hanning-windowed
of
the heart
rate
now complete.
dataset is
respiration
performing
extracts
is
information
and
and
results
resolution
reduced
selected
and
processed
decimation,
in
(A/
=
concurrently.
point
dataset.
0.016 Hz.
without
4096
a
dataset is Blackman filtered
and power spectral processing.
software
for direct
allowing
visual
comparison of
by
display
of
at
A plotting
the HRV
the respiratory
and
frequency
derived from HRV data.
Statistical Analysis
2.4.5
Data
the
waveform
(4)
Verification
FIR25
process
respiration spectrums
peak and
of
spectral content
EKG
recorded
Respiratory Frequency
A 64
the
obtain
A/
comparison
gation
t-tests,
between
involved mean,
Mann-
25Finite
control and
standard
Whitney U test,
impulse
response
(FIR)
study
deviation,
and
subjects
standard
in the
error,
are
brain
injury
paired and unpaired
the Signed Rank test.
digital filters
clinical
described in detail
Due to the large
by
Ziemer
[38,
investi
Student's
range
pp387-407].
of
values encountered
This
essary.
the
the
with
of
processing
study
the HRV data
University
was performed
by
was employed when nec
the Department
of
Biostatistics
at
Rochester Medical Center.
laboratory
analysis of
(1-10,000 fold), logarithmic transformation
statistical
University
The
at
45
METHODOLOGY
2
of
involving
and was
sepsis
likewise
in the
rabbit model utilized similar statistical
performed
Rochester Medical Center. These
those described
by
Shannon [31]. Appendix B
by
the Department
statistical
elaborates
of
techniques
in
more
Biostatistics
are consistent
detail.
3
RESULTS
Results
3
The
from the
results
ogy section,
The
which encompass pediatric
principle
evaluation
of autonomic
power.
colleagues
at
the
of
between brain
the
used
of
in
and
with
plasma
Score,
collaboration
Children's Critical Care
non-invasive
heart
with
Unit,
the
rate
detailed.
are
those detailed in
Glascow Coma Score
levels in
at
patients
time
and
additional
several
acquisition and
section.
blood pressure,
admission
power spectral
brain death
following
spec
Goldstein,
study, heart
of
establishment
Dr. Brahm
Methodology
mean
tool for the
variability
Rochester Medical Center. The primary
for this study
catecholamine
of a
and
severity
Table 1 lists the age, sex, heart rate, respiratory rate,
Glascow Coma
are
sepsis,
pediatric patients and
injury
conducted
Strong
University
analysis protocols
and rabbit
the Methodol
Injury Patients
research was
Associate Director
head trauma
tone in brain injured
correlations
This
investigations described in
hypothesis involved development
clinical
developing
tral
clinical and experimental
Pediatric Brain
3.1
of
46
compared
data
to those
Glascow Coma Score < 6.
Individuals
catecholamine
for
were analyzed
levels,
electrocardiogram
to
a response
and
a cold
and
respiratory parameters,
Results
test26.
pressor
are
serum
tabulated in
Table 2.
Figure 12 illustrates the
with
Glascow Coma Scale
herniation
graph, it
with
the
and
can
of
brain death.
be
seen
changes
that
3
(top),
in the blood
test
narrow
relies on an
pressure and pulse
and
Noting
use of a mechanical ventilator.
cold pressor
power spectral
rate,
the
the two
a significant
brain death. The very
26The
in
high
intact
same patient
points
decrease in
frequency
Normally,
density
which are regulated
brain-injured
24 hours later
marked as
LFP
peak amplitudes
peak
this HFP
neural reflex
of a
the
after cerebellar
and
in the top
is
much wider
and
is
used
to
HFP
on each
(i.e. power)
spike
pathway
by
(HFP)
patient
plot
occurs
is due to
(i.e. covering
stimulate an
autonomic nervous system.
increase
3
RESULTS
more
frequencies)
Figure 13
of
47
the
when
shows
patient
temporal
changes
brain death. Note that the
3/3
patients with
Figure 14
development
shows
temporal
patients
with
(NE)
levels
(E)
levels become
brain death.
the catecholamine
(pg/ml) during
in Figure 13.
same patients represented
and epinephrine
with
rate power approaches zero
plasma catecholamine
of
the development
in
almost
The third
the
Note that
non-detectable
patient
was
receiving
assay.
New Zealand White Rabbits
3.2
Results from 10
and
in
changes
total heart
during
brain death.
and
the development
dopamine that interfered
rate power spectra
low-frequency
brain death for the
of
spontaneously.
in heart
tonsillar herniation
plasma norepinephrine
in 2/3
breathes
anesthetized adult male rabbits
internal jugular
minutes after
(1.5 mg/kg)
mean,
[blood]
the
was
vein were cannulated
above procedure was
infused
and
pressure
(MAP)
were unchanged
by
a
over a six minute period.
and
and
tracheostomy
The
was
endotoxin
Statistical data
carotid
performed.
(1.5 mg/kg)
analysis
t-tests. After endotoxin,
low-frequency power (LFP)
the infusions.
in Table 3. The
shown
performed, E. Coli
deviation, log transformation,
standard
is
high-frequency
artery
Thirty
or saline
consisted of
mean arterial
decreased. Catecholamines levels
power
(HFP)
decreased in both
groups of animals.
After
administration of
low-frequency
that
HRV
a concurrent
power
the endotoxin,
is indicative
increase in circulating
a
of
decrease in
impending
mean arterial
septic shock
catecholamines
is
blood
in the
not evident
pressure and
rabbit.
between
Note
endotoxin
and control groups.
3.3
Software Application
Illustrations
of
dure using this
the
graphical output and numerical results
application appear
from
in Appendix D. The data
a normal analysis proce
represent
those
of a
repre-
3
RESULTS
Table 1:
Age,
48
sex, Glascow Coma
Score, basal
spectral values and plasma catecholamine
cardiorespiratory parameters, heart
levels (mean
S.E.M).
GCS
< 6
Brain Death
N
11
Sex
5 M
Age
5.9 1.4
6.8 2.2
Admission GCS
52
41
GCS
51
3
122 9
127 11
26 3
15 2
84 4
74 9
on
Heart
day
rate
of
study
(bpm)
Respiratory
rate
Mean blood
pressure
(bpm)
(mm
Hg)
Low-frequency
heart
rate amplitude
Low-frequency
heart
rate
High-frequency
heart
Norepinephrine
(pg/ml)
Epinephrine
tp <
0.02,
GCS
=
total
rate
total
power
tp < 0.03,
<
0.001
Glascow Coma Score
8 M
/
3 F
0.01795^
0.00406
(bpm2)
0.04089
0.01456
0.00047^
0.00024
(bpm2)
0.01127
0.00342
0.0008lt
0.00049
712
*p
4F
/
0.04125
1987
(pg/ml)
9
1.22264
(bpm2/Hz)
power
power
932
258
(N=5)
(N=4)
108*
21*
28
8
(N=10)
(N=10)
3
RESULTS
Table 2:
49
Cardiorespiratory,
testing. Data
cold pressor
power spectral and catecholamine changes
<
6
GCS < 6
+
N
3
(years)
3.6 2.2
HR
(bpm)
132
28
Brain Death
133
5.1 2.9
28
137
cold pressor
6
6
-
Brain Death
+
cold pressor
3
Age
and after
S.E.M.
expressed as mean
GCS
before
15
-
137 15
RR (per min)
32 9
38 7
17 3
17 3
Mean blood
88 15
88 17
67 10
65 9
0.06463t
0.03486
0.00022t
0.00024
0.04874
0.01223
0.00005
0.00007
0.00603t
0.00573
0.00097t
0.00097
0.00087
0.00145
0.00075
0.00074
4221*
4318
103*
135
(mm
pressure
Hg)
Low-frequency
power
(bpm2)
High-frequency
power
(bpm2)
Norepinephrine
GCS
0.0001,
=
3200
(N=3)
(Pg/ml)
tp <
2992
*p <
0.05
Glascow Coma Score
16
30
3
RESULTS
50
4.00 T
SEVERE BRAIN INJURY
GCS
3.20
-
2.40
"
"
1.00
-
-
0.80
"
3
=
"
a00
0.40
*-
BRAIN DEATH
GCS
0.32
-
-
0.24
-
-
one
aos
-
-
LFP
-
HFP
1-
H
0,0
1
1
I
0.4
0.2
Figure 12: Changes in
and
GCS=3
power spectral
(top)
and
the
density
h
ae
FREQUENCY
patient with
3
--
-
0.00
=
of
same patient
1
1.0
(Hz)
HRV in
a
four-month
24 hours later
brain death (bottom). Note lOx difference in
1
as
old
brain injured
after cerebellar
magnitude of
the Y-axis
herniation
scales.
3
RESULTS
51
0.08
-,
o
Patient 1
o
0.06
?
-
Patient 2
-J
<
H
Patient 3
<
z
til
0.04
-
0.02
-
.o
w
c
u
OS
fa
I
o
-J
Figure 13:
0.00
Temporal
changes
in heart
brain death. Low-frequency total heart
tonsillar herniation
and
brain death.
rate
power
spectra
during
rate power approaches zero
the development
in 3/3
of
patients with
52
RESULTS
3
=
3000
Patient 1
a
[NE]
[E]
Patient 3
Figure 14: Temporal
opment of
almost
patient
changes
in
brain death. Plasma
non-detectable
was
receiving
in 2/3
plasma catecholamine
norepinephrine
patients
with
(NE)
levels
dopamine that interfered
with
the
[NE]
?
[El
(pg/ml) during
and epinephrine
the development
o
of
(E)
the devel
levels become
brain death. The third
catecholamine
assay.
3
RESULTS
53
Table 3: Changes in
various
the New Zealand White
physiologic parameters
rabbit,
(mean
Basal
146
rate
in
endotoxin shock
S.E.M.)
Control
Heart
resulting from
60
13
Endotoxin
(N=4)
minutes
18+
179
Conditional?
Basal
20
159
(N=6)
35+
224
(bpm)
Mean
85
arterial pressure
(MAP)
(mm
5
77
2
82
7
62
5+
Hg)
Log Low-frequency
power
-4.78
0.89
-4.13
0.724
-4.85
0.93
-6.35
-2.78
1.16
-5.40
0.97+
-3.90
0.90
-5.33
1.98+
(Log bpm2)
Log High-frequency
power
0.73+
(Log bpm2)
Norepinephrine
Epinephrine
Dopamine
(pg/ml)
(pg/ml)
(pg/ml)
+p < 0.05, ^Decrease in
127
118
114
91
92
40
111 45
21
0
21
0
28
17
26
8
41
0
54
16
50
22
66
59
MAP
>
20
mm
Hg
3
RESULTS
sentative control
data
listing,
The
The
menu
New Zealand White
developed
overlay design
structure
during
in the
are
this
A
cover
illustrating
summary sheet,
possible
allowed
a
work was structured
modular
design for the
The detailed structure,
in
menu
numerous
section.
frequency band
form
and employed
future
of
the
additions.
processing,
analysis
its
operator
and an explanation of
included in Appendix E. The processing details
Methodology
a
output, is included.
which allowed modular changes and potential
and graphical output stages.
interface,
rabbit.
and several graphic plots
software
a program
54
software are explained
DISCUSSION
4
55
Discussion
4
4.1
Acquisition/ Analysis
Hardware Requirements
4.1.1
Different hardware
during
actual
data
was utilized
development
the
A
listing
of
from
stages
These differences did
require special precautions when
application environment.
shown
during
collection and analysis.
difficulties but did
is
Software Development
the
not
what was employed
introduce
software was
the different hardware
significant
introduced to the
used and pertinent quantities
in Table 4.
Table 4: Hardware
used
for development
versus actual application use.
HARDWARE
DEVELOPMENT
CLINICAL APPLICATION
Personal
IBM PS/2 Model 30-286/10
AST Premium 386/25
2048 bytes
2048 bytes
Hewlett-Packard Think Jet
Hewlett-Packard LaserJet II
Data Translation DT-2805
Data Translation DT-2801-A
2.5
1.25
computer
Hard disk
cluster size
Printer
Data
D/A
acquisition
base
card
(D/A)
card
resolution
Data Translation DT-707-T
D/A terminal board
The development
of
the EKG
was
and
development
of
of
the
software
respiration
it
developed,
was
signals
Hz for 5
perform
progressed
a
data
in
of
the
stages
High
of
software
the
stages.
As
each additional procedure
master/controlling
to
minimize
were
program.
In the early
produced, but in
potential
operator
later
error
development involved creating the data
rates were required
hence, data
Data Translation DT-707
and
during
(i.e. 'idiot-proofing').
software
acquisition
channels),
were added
microseconds
acquisition and subsequent analysis
the algorithms, only necessary functions
implementation
algorithm.
to
incorporated into
final versions, safety features
The first
microseconds
were
transferred
for
acquisition
multi-channel acquisitions
directly
to
a
(i.e. 5000
hard disk file. The ASYST
4
DISCUSSION
56
for this
software package employed
directly
acquisition
The layout
to
the target disk
2.4.1,
the
acquisition
data
cluster size
is 2048 bytes (2
the
allocation
meant
the
reason
that 1024
disk file
and
in
five,
Disk file
data
single-precision
of
the
storage
for data
a nominal
integer format
in
original
integer
hardware utilized, the disk
smallest allocation unit
in integer
for
a
multiples
Numeric data resulting from the data
which used
one allocation unit of
1024
recording
requirements
is the
As
to be known.
the
storage of
acquisition was performed
subfiles used was
for
procedures
and needed
present
size and
were represented as columns
size requirements
Table 5:
during
values were contained
the length
between two
in
(i.e. 2,4,6,... kilobytes).
unit
acquisition process was
this
for data
subfile size used
kilobytes27)
disk. Data transferred to disk
of
important
was
hardware dependent. For the
was
built-in
several
disk file.
computer
structure of
in Section
mentioned
work possesses
of
256
channels
subfile structure.
subfiles
is
for D/A integer data for
per
value,
2 kilobytes. This
Multiple
values.
in the
two bytes
shown
A
was
recorded,
listing
of
in Table 5.
nominal
256
subfile
recording.
Number
It
was
storage
sufficiently large
for
Channels
directly
and
on
1,050,624
3
1,574,912
4
2,099,200
5
2,623,488
medium,
introduced
1024 bytes.
data to
timing
the hard disk
contains
of
a
and
errors
(bytes)
high capacity Bernoulli cartridge, the
was not practical since
storage and subsequent processing.
27One kilobyte
Required Space
2
found that direct transfer
intended data
recorded
of
in the
Bernoulli disk
recorded
access
data.
times
Thus, data
then later transferred to the Bernoulli
The data transfer
rate
to hard disk
was
were
was
cartridge
determined
4
DISCUSSION
to be
by
sufficient
for
Tektronix
a
To
all expected acquisition rates and
was verified
model
CFG250 function
in the development
aid
Packard monitors,
of
57
models
test
The bandwidth
signals.
determined to be
was
noise,
Analyzer
model
3562A
satisfy the
allowed
an
Sampling
accuracy
also
were obtained on
signals
480 hertz
about
of
1
0.5
with
Nyquist
the
loan
in
distorted
later processing
use of a
of
locating
due to
sections
included
signal
only in those EKG
from
a
University
volunteer
environmental
and
as
line
Hewlett-Packard Systems
from Hewlett-Packard. The
rate
sampling
of
1000 hertz to
960 Hz. The 1000 Hz
the R-wave
peaks
rate
thus
in the EKG
records without anomalous voltage
patient movements.
because
algorithms
loan from the
recorded
directly
frequency
milliseconds
preserved
or
which
in selecting the
a
were
Hewlettalgorithm, two
of
its inherit
The 1000 hertz
one millisecond
period.
sampling
QRS Complex Detection
4.1.2
Some
simplified
78212D,
these signals,
of
theorem for
fluctuations (i.e. noise)
value
QRS-complex detection
Physiologic
resulted
This accuracy is
signal.
and
signals supplied
generator.
which was obtained on
determined bandwidth
assumptions
processing.
in the
The fiducial
nature of
understood
ends after
constant
to initiate
P-R interval
three
of
the
with
for the duration
EKG
with
of
'firing'
of
the
of
the
sampled at
program was
cardiac
the R-wave
cycle since
the
by
were
[22,
p59], the
mean
determined to be
peak.
cardiac
the
In
The
cycle
P-wave,
remains
under normal conditions.
Rompelman
1000 Hz
held throughout the
is that the P-R interval
recorded signal
by
the
waveform were
the SA node, indicated
assumption made
the P-R interval
of an
for
central region
the T-wave. The
the constancy
the derived HRV
point searched
R-wave is actually in the
of
78213C
Rochester Medical Center.
the
of
test
by
is
and
relatively
testing
of
differences in the
zero with a variance
milliseconds.
Since the EKG sampling
rate used
in this
work was
1000
Hz,
the accuracy in
locating
4
DISCUSSION
the R-wave
this
the SA
msec,
in
the
node
SA
the
eee
,
Figure 15: An
results
node
3
.
is 3.5
point
in
6
For
milliseconds.
P-R intervals
less than
the
was
was performed
held.
Including
cumulative error
a mean
heart
rate of
ee
9
.
ee
12. e
is. e
is.e
21. e
5
26.5
29.5
32.5
35.5
38.5
41
se.e
53.9
56. e
59. e
62. b
4
76.4
79.4
e
44. e
47
61
.
4
64. 4
67.4
example
EKG
.
locating
(3.5/750)
one-half of one percent
23.5
.
the
80 BPM (750
29.5
41
in
for
in time.
point
.
of
Rompelman,
a mean error of
trigger
ee
No testing
P-R interval constancy
the P-R variance from
triggering
period), this
milliseconds.
above assumption of
error and
locating
10.5
peaks was
work since
detection
58
e
73
waveform
.
illustrating
anomalous occurrences
in the
second
panel.
Tlie final QRS-complex detection
from
the
an
earlier
form.
The
original
same current sort/index method
proximity
ings
reduced
of
and voltage excursion
the
original
movements) to be
version
for
algorithm
described in Section 2.4.1 bad
form
to locate
employed
QRS
a single
complexes.
validation of candidate
It
R-wave
as
valid
R-wave
peaks
(see Figure 7
window
peaks.
The
shortcom
and glitches
on
page
using
temporal
also utilized
large T-waves
mainly involved allowing
accepted
scan-
evolved
35).
(patient
Another
4
DISCUSSION
59
3599
xEB
3399e
3999
--
2 5 99
--
r-A]
2999
1599
lee
pe.kA
--
--
%i
I
l
I
3.1,4
3.L,:
I
I. 69
3TT&8
XE4
Figure 16: An
problem was
the
improper identification
discussed
also
scan-
windows
previously.
before confirming
a
the
Patching
marily due to
of
More
Method.
patient
Anomalies
complexes
these
reliable
of
an example
'sliced'
'sliced'
was
This
with
such as
those
which
in
the
this
example
{IHR.
panel
in Figures 16
2
of
34
addition was
R-wave
peaks
sometimes also
in the
the
was
can
17,
pri
due
second panel of
Values} dataset,
seconds and %
and
Figure 15
adjacent
during data recording,
shown
at ss
combining
implemented.
is
anomalies
are shown
shown
of
of valid
still occurred
phenomena
edge,
complexes near and at
the technique
identification
EKG tracing.
a scan-window
(muscle twitch, cough, etc.), but
derived. The
examination,
by
QRS
Concurrent
complex.
Spurious transients
movements
in Figure 10 (page 40),
closer
QRS
in
zoom-window approach was adopted and
Figure 15. This EKG is the trace from
for
seconds
the introduction
spurious cardiac electrical activity.
enlarged
34
observation of
detected
the 'zoom-window'.
obtained when
to
The
window edges prompted
concept of
IHR
anomalous point at %
shown
40 seconds,
respectively.
be identified
immediately
4
DISCUSSION
60
40051
peak
C
3209
E0
2899
--
4B396
2499
2999
16 89
D
peak
--
41166
peak
--
--
1298
89
I
^
I
4.1,5
1
4.k3
^^9
4.21
xE4
Figure 17: An
data recording
after
that time to
accept
transients in the
algorithm
shown
anomeous point at =
by
the data
dataset
inspection
visual
be
18, illustrates
the
of
the data.
in
an example
EKG
Judgement
would
with
a new recording.
removed
later
during
described in Section 2.4.2. An
in Figure
seconds
it
or replace
would
40
extraction of
the two
effects
Smaller
tracing.
be
made
at
or unnoticed
the processing
by
{IHR.
(from Figure 10),
anomalies
Values}
the IHR.Patch
in Figure 15 introduce into
the IHR dataset.
4.1.3
The
Respiration Signal Analysis
respiration
spectral
able.
density
The
greater
reason
frequency
of
the HRV
is that
than 0.15 Hz
prompted
can
usually be identified
dataset, however,
subjects
and
the development
finding
breathing
the true
of a procedure
on
a graphical
confirmation
by
display
to
extract
the
alternate means
spontaneously may have
respiration
of
frequency
a
is desir
broad band
may be difficult.
the dominant
respiration
power
signal
This
frequency
4
DISCUSSION
198.
69.
61
--
^sto
I
3"sti
I
Figure 18: Extraction from {IHR.
in
example
EKG
waveform.
iste
Values}
I
slt~e
dataset
1
lt~e
illustrating
'
Tile
effects anomalous
points
DISCUSSION
4
from the
The
heart
respiration signal recorded with
analysis of
directly from
the
However,
minute
The
rate of
as
large
as
a
4096
The
mately
-70
dB
Figure 19
was
and
to
16,384
These
in the
high-frequency
digital filter
the
1000 Hz.
being
262,144.
from the
data
of points
from the
point
This
per
reduced-point
and possessed an
caused a problem.
had
original signal
dataset if the
at
number
sixteenth
dataset.
point
obtained
over-sampled
seconds of respiration
This, however,
noise
every
its
be
20-30 breaths
in the
reduction
re-sample
a
yield
a
order of
being
was
recorded
was
of
significant
components
original
would
respiration
frequency
have introduced
dataset
respiration signal was processed
with subsequent extraction of
every
com
16</,
were
by
a
simply
finite im
point resulted
dataset.
at
of
the digital filter include
30 Hertz. This
sampling
cutoff
rate of
the FIR digital filter
62.5 Hz for the
used was
respiration signals
ture detail the derivation
129
28Decimation here implies
which would appear as
the
and
the
position.
were recorded
directly,
from EKG
called
a removal of sampled values
sampled at a
lower
frequency
Sampling
the
in
rate.
of approxi
theorem for the
reduced-point respiration
index
electrocardiology
to have been
satisfies
points
of respiration signals
a concept of scalar
a cutoff rate and
frequency
as coefficient value plotted versus
Although the
involves
line
480 Hz.
(FIR)
effective
of
to
second segment of
parameters
intended
length
point
content
signal
the
on
could
recorded, that
were
is
children
the full 262.144
reduced-point
decimated28. A 64
pulse response
points
for
frequency
activity
the EKG
respiration
62.5 Hz.
environmental and
abasing into the
in
262,144
of
respiration
points as
The intent here
order.
sampling
ponents
data
frequency
of respiration
in
The
signal.
Thus the
was representative of
effective
signal.
differed from that for EKG processing
signal
normal respiration rate
dataset
original
recorded
0.3-0.5 Hz.
standpoint
data
the
same number of
the
or
appeared
the respiratory
the EKG
variability in that the fundamental respiratory
rate
Hence,
62
dataset. The
coefficient values shown
methods
signals
[25,
found in the litera
27]. This
electrical axis of
an ordered
in
fashion to
approach
the EKG
result
in
a
signal.
dataset
4
63
DISCUSSION
FIR
0.035
-|
D igital
i
F liter Coefficients
i
i
i
i
0.030
f
+
+
+
+
QJ
0.025
-
ro
>
0.020
C
QJ
0.015
-
U
1
Lu-
0.010
-
Ll-
QJ
o
0.005
\
-
"0.5
dB
Stopband Ripple:
"70
dB_
Passband Freq.:
10 Hz
\
-
W
-.005
1000 Hz
Passband Ripple:
+
t
-
u
0.000
Sampling
taps
Freq.:
+ Stopband Freq.: 30 Hz
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
1
%
-1-
-
H
129
Length:
J$\_
-
i
-
1
I
20
40
60
of
FIR digital filter
100
80
Coefficient
Figure 19: Plot
f-
1
h
1
1
120
140
Index
coefficients
versus coefficient
index.
4
DISCUSSION
These latter
employed
in the
from
interesting
methods were
a signal
standpoint
processing
but
were not
current work.
Application Features.
4.1.4
The
64
itself lends itself to
software application
efforts
as
are
through the
The
display
completed at
Many
error-
point
that
in
listing
of useful
during
would
and
the
the
the
enables
listings
graphical
the
with
useful
allows
space
the
below.
steps
processing
and
reprocessing
have
hopefully
eliminate,
interrupt the
analysis
data
of
data using
at
differing
data.
to be
include:
file
performed without
deletion,
exiting
file copying,
and
indicated.
display
immediately
is facilitated
which contained processed
operations
operations
disk free
utility that
This is especially
of
basic DOS
Those DOS
application.
directory
A
which allows
crunching
data.
file,
analysis parameters or re-examination of 6uch
A file utility
given
occur which would
disk
a
program
which
included to minimize,
This
analysis.
the
features is
indicating
of processed
retrieve,
with
simple number
analysis.
normally
loss
possible
store
during
Interaction
procedures are
operational errors
A capability to
text.
maintains an area
point
any
checking
process and result
any
previous
displays. A
use of menu
main menu
been
any
described in
than
much more
after
of all channels recorded
data
collection
to
to
ascertain
a
the
data file.
integrity
recorded waveforms.
A utility to
related
allow
plotting
the
on
same
display
multiple graphs of related or
non-
information.
A utility to
frequency
allow
band
the
operator
widths
based
to
alter various search and analysis parameters and
upon specific
dataset
characteristics.
4
DISCUSSION
65
The capability to
obtain a printer
Useful dataset
cation.
hard copy
of
during
statistics obtained
graph
any
displayed in the
the processing
appli
included in the
are
display.
Within the data
and
time
are
acquisition
procedure, the
'stamped'
automatically
as a comment at
A file utility to enter, examine,
entry
This
application
for
cedures
analysis
originally designed
been
important to
of notations
made which
blood
with
this
the time
of
the
date,
recording.
the data files
enables
each studied subject.
expansion
in
pressure
to include future processing
expansion
pressure waveforms.
include blood
channels, file name,
and alter comments within
has the capability for
of
number of
mind.
The data
In
fact,
acquisition
procedure was
recordings
many
pro
have already
information.
Software Limitations & Operational Notes
4.1.5
The
method employed
rate
dataset
of
these data
quent
are
removed
disruption
data
removes
in
still
points
of
the heart
remains.
rate
data
would not
evaluated
for the instantaneous heart
divisor
should represent
non-linear
amount
(1/4095
has
been
not
points
interpolation
the
the
being
series
number of points
tion 2.4.1
During
in the instantaneous heart
constructed
of
of
but
rate
the
median
would
resolved as of
1/4096),
this date.
filter
effectively
mentioned
alter
to
produce
points
their
the
in Sec
value as
{HRV. Values}, the
intervals in the target array
a
subse
dataset.
{IHR.Array}
number of
to
for the
detected, but
originally
(4096). The difference in the resulting
as opposed
removal
variability dataset. It is true that few
Implementation
remove
points
from the {Peak. Indexes} dataset. The
to the
comparison
number of points
spurious
disrupts the time-event
points
development
for correcting
difference
of
values
0.025
(4095),
differ
percent.
by
This
not
the
a small
situation
DISCUSSION
4
During
the
was
66
window
was
Hanning
amplitude
window of
expressed
is exactly
in the
This
Clinical
Brain Injury.
For many years,
in
blood pressure,
cardiac
output,
body, including
the
while certain
was
a
density,
not
been
quasi-steady
states
(as
would also
well as
is
stimulated
by
state with
are
In the literature,
ity
are
frequency
by
high-frequency
brain injured
and
29
A
the
nervous
has
sympathetic
Hz)
is
window of
a rectangular
the signal,
as
was not a valid
injury
heart
change
exist
the
with
an
in baseline heart rate,
many
systems of
a state of chaos
most
increasing
study
rate
in
autonomic cardio
instead
behaviour
regularity
reported
variability,
chaotic
the
herein has
even when
and
non-
revealed
the
body
cardiovascular
one
in
which
the
heart
and
parasympathetic
rate
current
variability
are
study, there
low-frequency
nervous
solely
systems.
mediated
was a moderate
power
neural pathways
perceives
as
are
High-
by
the
decrease
between the severely
(Table 1). This implies that both the
body
rate variabil
low-frequency fluctuations (0.04-0.15 Hz)
decrease in
patients
analysis of
that
in heart
In the
system.
brain dead
noxious stimulus
thought to
aging) illustrate
revealed
and a significant
and parasympathetic
it
this date.
Recently,
information derived from the
fluctuations (0.15-1.0
parasympathetic
in
spectral
mediated
since
noxious stimulus29.
via non-invasive methods
jointly
by
power of
held that the
little
associated
associated with almost no
strong
Hanning
a
be halved. This
resolved as of
variability in these behaviours [13]. The brain
that brain death is
by
that the
and vascular resistance.
system,
originally done
was
same signal multiplied
assumed
Values},
Result Interpretation
[13]. As such, health is
disease
the
medical practitioners
cardiovascular
state
This
two.
of
then
Laboratory
and
to the Blackman filtered {HRV.
area of a signal multiplied
It
has
vascular system existed
steady
factor
a
power spectral
situation
window
one-half as
amplitude.
unity
statement.
one of
by
multiplied
determined that the total
unity
4.2
the
application of
sympathetic
irrevocably damaged between
potentially tissue damaging.
4
DISCUSSION
severe
brain
Several
the
67
injury
and
brain death.
cold pressor
test
test is designed to
the
and
to
blood
pressure of
beats
per minute occurs
blood
24
increase in
7 mmHg
for the
adults
by
serum
an average of
In the brain
cardiovascular
injury
27
frequency
heart
but these
changes were not
These
of subjects).
fluctuations
pathways
results
other
of
elevated
period
brain dead
linear-type
An
The
due to
are
cold pressor
a constriction
An increase in
stimulus.
increase in the heart
[29]. Serum
of which
rate of
10
2
from
catecholamines
which normal values of
447 pg/ml, respectively [37].
During
levels increase in
normal
norepinephrine
139 pg/ml, respectively [29].
was no measurable response
in
during
patients with
significant
that there is
severe
Small
testing.
cold pressor
were evident
6)
a
(most
injury
in
autonomic
absolute changes
in
low-
Glascow Coma Scale <
likely due
disruption
brain
of
the
to the
6,
small number
efferent
and complete
occurred
norepinephrine
but
near
undetectable
in the brain dead
catecholamines
patients.
measure of
and
epinephrine
within
24 hours
sympathetic
interruption
of
of
brain
levels
of
subset of
their
these
same
injury,
cate
three brain dead
injury, however,
levels
after
similar
of plasma catecholamines
severity in the brain injured. With
of severe
in the severely brain
near undetectable
This indicates that the level
varying levels
A
patients.
levels dropped to
catecholamine
catecholamines with
determined
to
imply
cholamines were characteristic
24-48 hour
and
studied, there
injured (Glascow Coma Scale <
had
pg/ml and
two
in brain death.
Elevated levels
patients
71
statistically
neural pathways
cardiovascular
these
rate
a
pg/ml and
response
the
testing laboratory for
by
epinephrine
pressure
region of
average normal adult
population
activity in
blood
concomitant with an
samples are analyzed
testing,
pressor
arterial
heat in the
conserve
epinephrine and norepinephrine were
cold
dysfunction,
of autonomic
measurement of plasma catecholamines.
stimulate an
of cutaneous vasculature
collected
for the detection
methods exist
is
a
to
not a
precise measurement of plasma
a non-linear correlation
may be
with additional studies.
aim of
the
current
study
was
to
seek
a correlation
between heart
rate
variabil-
4
DISCUSSION
ity
spectral power
No direct
serum
jury.
(linear)
levels
the levels
and
the
decreases steadily
results
catecholamines
during brain
(epinephrine
increase
death. This is in
From the information
of variations
in
documenting
with
existing
of
corroborative
brain
during
injury
severe
levels increase
brain
Woolf
during
heart
injury
[37]
but
of
the
brain injury.
variability
rate
drop
brain in
power
variability
to
brain death.
near zero
that in
who reported
severe
levels
humans,
brain injury.
methods
non-invasive
power and
severe
during
immediately following
in the behaviour
developed
autonomic cardiovascular system
brain death. This technique
definitively
severe
and are near zero
in this study, the
tests to
rate
norepinephrine)
low-frequency
agreement with
obtained
for the detection
useful
and
indicate that total
epinephrine and norepinephrine
may be
determined between heart
the severity
with
during
of plasma catecholamines
correlation was
of catecholamines
However,
Plasma
68
establish
could
be
in
used
conjunction
brain death in humans. Further
studies seem warranted.
Septic Shock.
creases
following
levels.
cholamine
cert
with
arterial
The
sepsis
rabbit
endotoxin-induced
blood
pressure
during
levels is
not sufficient
the
system
is primarily
plasma catecholamine
pathetic
is
levels
and
activity is inhibited
suggested
that inhibition
sepsis
may
research
involving
provide more
identify
decreased
the
the
by
blood
power
Thus the
shock.
cate
decreased in
con
sole
onset of septic shock
low-frequency
neural
power
onset of septic shock.
activity
by
de
increase in
a concurrent
variability
pressure
in
monitoring
of
Since
rabbits.
activity, depressed
may indicate that
sym
From this conclusion, it
endotoxin
contributes,
at
of endotoxin shock.
the
insight
arterial
sympathetic
of sympathetic efferent
least in part, to the development
Further
to
rate
endotoxin
regulated
during
mean
septic shock without
However, low-frequency heart
catecholamine
endocrine
study indicated
changes
on specific
in
autonomic
mechanisms
cardiovascular
activity
of sympathetic neural
during
inhibition.
5
CONCLUSION AND RECOMMENDATIONS
Conclusion
5
This
software application
function
cardiovascular
pressure analysis
states should
be
Relationship
improved
derstanding
would
sults
the
of
by
pursued.
non-invasive means.
these
term
work
of a
internment)
iological
be
characterization of autonomic
development into blood
program
of other physiological conditions and
disease
Brain
Recovering
brain
power
region
injury
compared
(0.01-0.15
patients.
spectrum of
follow-up
Injury
more complete un
the heart
examinations
to the
tend to indicate
Hz)
A
previous
of
Patient.
rate
these
data
variability
patient.
collected
Re
(during
for further investigation.
Cardiac Feedback-Control Model.
may
contribute
teractions between the
findings from
out-patient
would
Further
low-frequency
in the
in the
follow.
of pediatric
changes
examinations
patient's original
This
reasons
levels in the
for recovery
long
Development
investigations
Several
be facilitated through
of
a significant asset
Spectral Power to the
power
chances
Recommendations
has been
and clinical
of
Increasing
and
69
to the development
cardiovascular
additional studies of
abnormalities
may be
a
autonomic
and
heart
rate
forthright
of a
feedback-control
nervous
variability using
endeavor
in
systems.
model of
Integration
in
of
subjects with various phys
developing
these feedback-control
models.
Future Investigation into Arterial Blood Pressure Variations.
Research to employ
pressure waveforms
inclusion
of
blood
ration signals will
spectral
analysis
is currently underway
pressure
information
facilitate further
at
methods
to investigate
the Rochester Institute
during
the
variations
of
Technology. The
original acquisition of
studies of pediatric
brain
injury
in blood
EKG
patients.
and respi
The study
5
CONCLUSION AND RECOMMENDATIONS
of correlations
between heart
variations
open avenues of
may
rate
variability,
70
catecholamines
understanding into the
levels,
mechanisms
and
blood
regulating
pressure
cardiovas
cular activity.
Potential Applications.
Efforts to
develop
non-invasive means
real-time
is
being
portable analysis
may
processing
of
considered at
prove
very
useful
the EKG to
units which evaluate
for
extract
this time. This
clinical use.
As
rate
mentioned
spectral content of
would provide
heart
variability
in Section 1.4.3,
the derived HRV
bedside data
by
signal
on cardiac autonomic
efferent activity.
There
propriate
from
are also
potential
treatment
exposure
therefore be
autonomic
to
able
applications
of wounded personnel.
certain
to
military
assist
disruptions.
chemicals
or
for immediate field diagnosis
Corruption
biologic toxins.
in identification
of autonomic control
A
and subsequent
portable
treatment
analysis
and
may
ap
result
unit
may
for
such
protocols
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Appendix A
Signal
The processing
separate
of signals entails
nents.
Signal
with a
summing junction circuit,
involves many steps,
types
appendix
include Ziemer
[38],
Continuous-time
their domain.
of
analog
A. 1.1
Any
composite
Hewlett-Packard
Analog
these two
signal will
involved
signals are
in time.
as
multiple
mono-
frequency
of spectral
that
from
and verbal
this
are also
discussions
tech
identification,
a
several published
with
few different
which
sources
engineering faculty.
Signals
every
signals which possess a value of
Obviously then,
a continuous-time
signals
spectral content.
possess a unique value at
For the
compo
constitutive
complex modulation
employing
described below. There
[19],
those
into their
extract
from
construction of a signal
component30
purposes
Analog
characteristics.
imply
adding
work extracted
signals are signals
a selected point
both
a
as
signals
be handled uniquely to
Continuous-Time
A.l
for
is
simply
some of which are
of signals which must
This
or as
for the
decomposition,
general operations:
of complex
construction can occur as
Signal
niques.
two
decomposition
and
sources,
Fundamentals
Processing
a continuous-time
remainder of
analog
this
point of
infinite
analog
discussion,
time in
resolution
signal possesses
reference
to
an
signal.
The Fourier Series
signal
summation
or
waveform
of weighted
of a
periodic
sinusoids.
nature
This
can
summation
Fourier
series representation of a periodic waveform.
Fourier
series
30Spectral
representing
components
some
consist
of
waveform, x(t),
the
be
amplitude
component.
76
and
represented
is
more
by
an
infinite
commonly known
Equation A-l
shows a
series
as
trigonometric
in the time domain. The Fourier
phase
shift
for
each
the
contributing
series
frequency
APPENDIX A
77
coefficients31, an
bn
and
mean value of x(t
)
over
be
must
for
evaluated
the time domain. A fundamental
PC
x(t
)
=
a0 +
series
complex exponential
is
2J
form,
nwo'
+
x(t)
=
other
A0
5Z ^n
ways,
Equations A-2
shown as
is denoted
to the
as u>o.
(A-l)
sin nu>u
n=l
in two
expressed
frequency
evaluates
ex
a" cos
n=l
The Fourier
The a0 term
each x(t).
An
+
a cosine
and
cos{nu0t
A-3,
+
trigonometric
form
and a
respectively.
(A-2)
6n)
n=l
oo
XneT""*
(A-3)
x(t)=
oo
n=
The
coefficients
obtained
are
cients
for the
indirectly from
for the
the Euler
A Sample Case.
An
the
represents a real
cosine
a new
function
after
=
yi(0 + lfe(0 + 3/3(0
Y(t)
=
5cos(2a;0f +
function.
coeffi
series coefficients
07r)
component
+
the
(A-4)
series
shortly.
signal, Y(t).
Y(t)
31The Fourier
6n,
directly from
dt
x{t)e-^^
introduced
combining three
different frequencies to form
tion A-5
are obtained
and
The
for Equation A-l.
A-3), Xn,
using the Fourier
example of
process of
I
T0 Jt0
=
concepts of spectral components
form,
used
A-2), A0, A,
a single step.
Xn
tion
coefficients
form (Equation
complex exponential
Equation A-4 in
the
trigonometric form (Equation
cosine
is
shown
Equation A-5
signals
{yi(t),
below to illustrate
illustrates, in
yi{t),
It important here to
and
note
by
y3(t))
of
that Equa
summation.
3cos(8u;uf-7r/6) + lcos(16u;uf + tt/3)
are obtained
equa
an
integration
of
the
product of
x(t)
(A-5)
and a sine or
APPENDIX A
The
78
Figures A-l
by
components
are
for
signal.
content,
of x(t).
multiples or
Band-limited
The
harmonics
say
in the Fourier
are needed
and complex exponential
obtaining the
frequency of,
maximum
signal
summed
dif
of
signals
of
these
Analog Signals
of
trigonometric
directly
spectral
integer
component
the composite,
shows
illustrated
A-5, is
in Equation
the three
which shows
Figure A-2
phase.
signal given
in the time domain.
cosine
convenient
the
and
simple
Figure A-l
Spectral Content
Both the
or
A-2.
and
fering frequency
A. 1.2
the
construction process of
Mu>u,
series.
signals
have
of
frequencies
component
of
the
fundamental
frequency
very important
signal
place
u)u.
finite
in
signal
possesses a
number of
a
are
which
na>0,
If x(t)
x(t) is termed
series
component,
are expressed as
a maximum and
If this occurs, the
the Fourier
frequency
amplitude and phase of each
then only
a
forms
terms
(M)
band-limited
and will
processing
be
mentioned again.
Since there is
to
use
two
plots
an amplitude and phase
if
graphical
component amplitude versus
component phase versus
series,
cosine
two-sided
either
frequency
form
of
representation
frequency
frequency
trigonometric
for
or
spectra, the DC
of
the
is termed
is termed
complex
spectra are used
each component
coefficients
an amplitude
is desired.
spectrum,
component
display
the
(frequency
The
and
The form
a phase spectrum.
exponential, determines
to the
it is necessary
frequency,
of
whether
plot
the
plot of
the Fourier
one-sided
spectral components of x(t
of
zero)
of
or
). For
always possesses a phase
value of zero.
The One-Sided Spectrum.
The
be
frequency
plotted
frequency
in
value.
to form
spectrum
a one-sided
is
shown
coefficients
of
Equation
spectrum of x(t).
in Figure A-3. Note that
all
A-2, Au, An,
An
and
8n,
can
example of a one-sided
frequencies
are non-negative
79
APPENDIX A
!<>
-4.
=
3
o*a
<1 t
3
eoi
< t
>
?
!
wl< m>
<M>
1
0*>
!>
<llt
*
>
-
^/VWW\AA/WVWW
TSii-
7735
Figure A-l: Example
of
three mono-frequency analog
=
<t>
.ilV
l<t>
^*
t
Figure A-2: Example
?
!<>
rs^5
?
signals.
3<t>
'M5
r^(
lno.ili)
of summed
(composite)
signal.
APPENDIX A
80
Amplitude
0
2u>0
4ujo
6u>o
8u>0
lOa^o 12^ 14u;u 16u>u 18u;,j 20^
Frequency (radians/sec)
+ 7T/2
+ 7T/3
+ 7T/6
Phase
(radians)
0
2u>o
4u;0
6luu
8u;0
lOwu 12u;0 14u>u 16u>tj 18u>u 20^
-tt/6
-tt/3
-tt/2
Frequency (radians/sec)
Figure A-3: The
one-sided
frequency
spectrum of
the
example composite waveform.
APPENDIX A
81
6
Amplitude
5
4
3
t>
( >
2
i>
< t
1
T
T
-16u;(i
-12u;0
-80/0
4w0
-4u/0
80*0
12u;0
16u\,
(radians
Frequency
/sec)
+ 7T/2
Phase
+ 7T/3
(radians)
+ 7T/6
16u;0
-120^
-80)0
0
-4u>0
80^
4o>u
,
-tt/6
12o>u
16u;(,
Frequency (radians/sec)
-tt/3
tt/2
Figure A-4:
Note that
The two-sided
amplitude spectra
one-sided spectrum.
The
frequency
is
an even
phase spectra
spectrum
function
is
an odd
of
the
example
composite
with amplitudes one-half
function.
waveform.
those for the
APPENDIX A
82
The Two-Sided Spectrum.
The
that
for any
specific signal component of
may
exist as
indicated
(k<0)
negative
have
5u0)
trum has
'negative'
the
on
shown above
portion
is the
as
Although
exist.
is
representation
phase
for the
is
an
information
frequency
frequencies
right.
in the
useful
frequencies (i.e.
representation
on
left,
the
A- 7
a
is the
DC
about
odd
a
Ot
the
of
be dis
can
in Figure A-4. This two-sided
the center,
component at
complex exponential
frequency
of
portion
in the
is the
Ou^ (DC),
function. Note that the
coefficients
form33
spec
'positive'
and
of
the function
phase.
the
It
(-e-jUA
,
spectrum.
(-ej0v)
+
+
_eWe)
conjugates3^
A'0,
denned
ej(~ute^
=
even
function
and
large
ejW
(*e-i*/e\
( Lj*/3\
QeW3)
+
-e-J"/A
and
are complex
Except for
frequency, Jfcw0, is
an
e-j2^1
For
Two-sided to One-sided Spectrum Conversion.
sided
is
graphically in
seen
amplitude coefficients are one-half as
g-JlGWu*
(
_|_
for Equation A-3
be
amplitude
c-;*;0t
cients
can
\
one-sided spectrum.
+
33Euler's theorem,
coefficients
in Equation A-5. For the A"_2 term (first term shown), \e~^ , the
Y{t)=
'""The
A*. This implies that
negative
in the Xn
contained
spectrum as shown
Equation
amplitude and
Figure A-4 that
the
some amplitude and phase
complex coefficient
frequencies
meaning, the
and phase
two-sided
a
frequencies
Y(t)
no physical
the
presence of
(k>0)
and positive
magnitude
in
played
the
frequency32, ku0,
A-3) illustrates
frequencies.
complex
The
by
form (Equation
complex exponential
by
the
all
complex-valued
k for
f\ (coswt
-oo
< k <
jsinut), is
form
A'
a
jeuut
(A.6)
eJlGUut
,
real
signals, the
perfectly
Xn
symmetric
coefficients can
be
coeffi
double-
related
the
oo.
used
to
relate
trigonometric functions to
com
plex exponentials.
34Complex
the
complex
only the
vectors
conjugates are represented as phasors or a pair of
5-plane. Added together, the
imaginary
rotating in
opposite
directions in
vector components cancel each other which
real components with a combined magnitude of
2|X|.
leaves
APPENDIX A
A
and
8n
83
coefficients
An
=
from Equation A-2
2\Xn\
by
the
following
relationships:
Tm Xn
0
arg(A'n)
=
(A-7)
arctan
Re
An
and,
Au
|A'u|
[
=
x(t)dt
(A-8)
.
Discrete Signals
A. 2
A transformation
discrete
now
=
of
waveforms
though,
a
the Fourier
to
describe
discussion
of
series will result
in
a
form
of a
for
use with
For
is discussed in Section A. 2.1.
spectral content and
the definition
more appropriate
discrete
waveform
is in
order.
X(l)
f '
0
(a)
T
IT
Analog signal
.r(K
'
/T>.
-
x^nAi)
>-f
r=
.i/
S Samples
n
=
0. I.
(b) Sampled
Figure A-5: Representation
An analog,
continuous-time
time signal, x,(n), to be
this
process:
by
at a uniform
-
I
version
of a
a
\
.
signal, x(t),
processed
sampling x(t)
va/
=
discretely
must
digital
rate,
be
sampled
converted
computer.
and
analog
into
Two
a
signal.
digitized,
steps are
then quantizing the
discrete-
involved
with
signal value at
the
APPENDIX A
84
sampling instant to
result
is termed
digital
By
analog-to-
sampling the
time
At
of
some
1/ fs
=
N
using
=*
a
The
is illustrated
signal values
for
each sample.
frequency, fa (in hertz),
by Equation
(n
the
signal value
have
sampled values
{x(nAt)},
=
conversion of
digitized
fixed sampling
sampled points.
x,{n)
The
value.
conversion and yields a
seconds which
x{t)
=
A-9
a constant
and shown
0,1,2,..., N
x(t)
can
spacing in
in Figure A-5.
(A-9)
1)
-
be
Discrete Fourier Transform
A. 2.1
In Section A. 1.1,
plication of
required
the
exponential
Spectral
continuous
then only
analysis
continuous
of
a
just
series.
over
finite
However,
number of
terms
number of
convenience.
of
terms
unless
is, discrete
waveforms can
as continuous waveforms can
form
exponential
Note that the 27r/0*
of
and
through ap
Xn
coefficients
constraints.
x(t)
was
Sec
found to be
were necessary.
That
signals
the
integration
is developed in
This development for discrete
from the
evaluation of
waveforms
is
be
a
be
manner
represented as a sum of
represented
called
to that
similar
by
a sum of continuous
the discrete Fourier transform.
The discrete Fourier transform is derived
Discrete Fourier Transform Derivation.
directly
the
its domain because
infinite
was available
analog signal, x(t),
discrete
waveforms.
sinusoids
sinusoids.
Fourier
summation required an
band-limited,
discrete
spectral content of some
x(t) to be
ondly, the
for
discrete digital
a
original signal
by
approximated
in
the Fourier series,
which
k terms have been
is
reproduced
substituted35
for
here for
wut
and
n,
respectively.
oo
Xkei2kKfot
(A-10)
x(t)=
h=
oo
where,
Xk
35r
5The
circular
expressed
in
frequency,
u)0, is
^
=
related
radians per second and
f0 is
f
dt
(A-ll)
.
1 JT
to the
frequency term, /0, by
expressed
in
cycles
(points)
w0
=
2nf0.
per second.
The term u> is
APPENDIX A
85
Transformation
substitution
x(t),
results
tuted into
/,j,
and
appears
of
the Fourier series into the
terms into the
of approximated
in the sequence,
a:s(7iAi),for n
Equation A-ll for
T/N for dt.
The resulting
as a summation over
X*
=
The
x(t).
i
N-l
7F
E
^
In
regard
frequency
to the
and
=
*n
=
{A'jt}
represents
the
,
the
argument of
Recall that
The DFT is
in the
replaced
by
represents
sequence
include:
=
0, 1,
...,
nAt
is
signal
substi
for t, 1/T for
reduced
N-l.
and
(A-12)
series
term,
the development
of
are
A-10),
e~j2Kkht,
the
=
=
represents
form
in the
xn
(A-13)
(A-14)
0,l,...,iV-l)
generally
of
{x},
frequency
fc/u
DFT, /0
1/T,
Xk
in
value
frequency /0.
In
is determined from the
represents
=
results
Each
complex.
the fundamental
this
where
equations
xu,x\,...,xk.\.
=
x,(nAt)
JV-point time series,
of a
harmonic
(Equation
xn
the inverse
0,1,..., N-l)
=
(n
which
of a specific
and
in the time domain.
xn
^ E A>'(2^"\
values
Equation A-13
xn, Equation A-13
(k
The DFT
as
series:
S*"e-i(2,r/")B*.
exponential
the iV-point time
used
x(t) signal,
the DFT.
Fourier
during
1. This
Equation A-14. These two
as
for the iV-point time
contribution
the
for k
defined
now
is defined
(IDFT)
dataset containing N
exponential
term
of
-
the
of
as:
x,(nAt)e-i2imk,N
Equation A-14
Xk
Periodic Nature
the
pair
original
domain
iV
integral is algebraically
approximated
N terms
...,
requires
n=0
discrete Fourier transform
Fourier transform
0, 1, 2,
=
Discretization
equation.
other substitutions
The discrete Fourier transform (DFT)is
a
Xk
discrete Fourier transform
the
where
klh
T
harmonic
was
the
of
/y.
period of
series xn.
periodic
in iV-points because
summation which
forms
x(t).
of
the
periodic
nature of
the
e-^2v/N^nk
APPENDIX A
86
Proof:
By letting
the
new
k
k+N
=
expression
and
substituting into the
to the
evaluates
same
complex
value
exponential,
the
as
original
Given:
expression.
e-j(2*/N)n(k+N)
e-j{2K/N)nk-j(2v/N)nN
_
e-H?*IN)nke-Ji2*IN)nN
=
but
e-j(2rr/N)nN
g-j(2rnr)
_
j
_
thus the fact that
-j(2*/N)n(k+N)
the DFT is
proves
The
periodic nature of
the
in
reconstructed
illustrates this
time
a
xn
phenomena
The frequencies
{X,,}
dataset is N
could
be
'shifted'
by,
say,
and still remain periodic
spectrum of a
will
be
in
by {X}
size and
(y
-
some
l)
is
in time
range
to
one extra
frequency
the
from,
coefficients
Since N
points
in TV points,
T.
Figure A-6
period
signal.
l)/0 [hertz]. Since
frequency
(-y + lj /0 to (yj f0
asymmetric36
an
to
periodic
in those N points, this
range
two-sided
the
range
[hertz],
frequency
signal.
Recall from Section A. 1.2 concerning analog
36There is
the DFT is
with
{X}
signal x(t).
from 0/o-(iV
in N. This is effectively
band-limited
using the
arbitrary transient
periodic
points
k.
analog
and since
periodic
all
when
original
T seconds,
clearly for
represented
points
iV-points, for
the
replaces
period of
signal
in
e-j(2*/N)nk
the DFT is important
Recall that xn
reconstruct xn.
were obtained
periodic
_
element which
is:
y/o-
signals
that
a
two-sided
spectrum can
APPENDIX A
87
Actual
a)
b) Time
c)
Figure A-6: The
by
the DFT
be
converted
done for the
discrete
into
to
N. To
and
of
digital
compares
the
just
obtained
DFT,
on
if the
The
the
y/0
resulting from the
assumptions made
number
order of
must
operations
This increased
be
equal
computational
number of values
and
for TV
[38,
to
can
speed
series
an
a power of
enormous
2k
for integer k
and
values of
speed,
requires
the FFT
>
The
an
only
faster than the DFT
not come without restriction.
=
of
additions
for large
computational
operate much
two (i.e. TV
form
spectrum
and
developed. The FFT
differences between the DFT
p458].
multiplications
therefore increase
therefore
frequency
be
signal.
become
was
can also
an equivalent
a one-sided
analog
can
(FFT)
does
by invoking
of complex
TV2,
and
This
original signal was real.
term. Thus
for
as
the fast Fourier transform
TVlog2TV
TV,
be
number of operations
computer.
points,
Assumed input
record
discrete time
of a
the DFT.
of
the
})
A-8 but omitting the
compute a
algorithm called
a
({A
signal can
reduce
an order of
a one-sid^d spectrum
spectrum
Computation
required
record
algorithm.
Equations A-7
of a
the time
periodic nature of
input
on
number
0). Table A-l
algorithms
for
a
APPENDIX A
88
Table A-l: Comparison
of
Number
of
A. 2. 2
Three
They
methods are
are
detailed
FFT
2
4
48
16
3
16
960
128
8
64
16,128
768
21
256
261,120
4,096
64
1024
4,190,208
20,480
205
2048
16,769,024
45,056
372
4096
67,092,480
98,304
683
of
by
extraction of spectral
transform,
The
in itself in
information
auto-correlation
p463] but
uses a
correlation
can
[38,
The
The
method
time
[38,
analysis,
p463].
used
method
system
a
can yield a graph
section.
signals.
The
other
below.
technique that
involves multiplying the
cross-correlation method
for
is
discrete
and cross-correlation
following
briefly described
of
signal
to indicate
reveals periodic
by
a
time-shifted
similarities
(repeated
p463].
two different signals;
be
are
auto-correlation
units of
Cross-correlation.
but
[38,
FFT.
Discrete Signals
described for
Ziemer
and
Speed Factor
4
itself. The resulting dataset
version of
function
DFT
8
elements within a signal.
nique
Real Multiplications for the DFT
The discrete Fourier transform is detailed in the
Auto-correlation.
trends)
of
2
the discrete Fourier
are
Number
Points
Spectral Content
analysis.
two
the
one
is
most
identification
is
similar
likely
to the autocorrelation tech
used as a reference signal.
by determining
the
system's
Cross-
transfer
APPENDIX A
A.3
The
to
Considerations
process
certain
loss,
and
various
that
types
or
corruption,
are relevant
sampled
information,
in the
greater
enough.
selection of
of
frequency.
band-limited to
The DFT
sided
the
resolution.
spectrum
record.
the total
is
apparent
The Nyquist
a
that there
bandwidth if
there
are
section will
if
occur
the sampling
are:
number of points
discuss only those
discrete Fourier transform
at
frequency
of
ranging in
of
the
frequency
must
be
a
rate or
all
some
produce
that
frequency
the
signal
original
accurate
component
points
in that
in the
information
is sampled,
frequency (/at)
of a signal
signal.
the
/,
must
is
equal
Sampling
cycle of each
Sampling theorem,
signal
at
compo
must
be
/s/2.
information for the development
frequency from DC (0/,)
spectrum
the length
of
or
closely
spectrum
which
trade-off between
to /s/2.
is dependent
the time
DFT points, usually
limitations in the
to
similar
becomes very important. The Sam
possess
least two
frequency
Increasing
appear
if the DFT is to
at which
frequency
rate yields
number of
'wider'
gives
to
series
This is important in resolving low
Increasing
quency,
rate.
rate
words, to satisfy the
a maximum
time
sampled
other
frequency line)
of a
This
will
However,
can provide accurate spectral
frequency
('width'
In
these
of
results of an applied
frequency
the largest
faster than the Nyquist
nent
Some
duration (thus the
record
the sampling
signal, the
original
frequency
information may
of spectral
process.
The time-series, xn,
rapidly
than the Nyquist
to twice the
or
masking
attention
requires
xn.
pling theorem dictates that for the time
contained
discrete dataset
a
as well as others.
to affecting the
Theorem.
Sampling
signal, x(t), if
be
yield
the sampling
'noise',
of
to the time-series
spectral
to
signal
analog
during
exist
the Discretization Process
of
in the discretization process, total
sampled),
concepts
a
sampling
conditions
rate used
(DFT)
of
things
certain
The
89
record
spaced
upon
by increasing
frequency
volume of available
of
frequency
components.
the sampling fre
higher frequencies.
resolution
data
resolution
the length
increases the
frequency
encompasses
The
of a one
storage.
and
It
frequency
High sampling
APPENDIX A
rates
for
A. 3.1
90
long durations
in
enormous
data
storage requirements
Spectral Abberations
AIiasinS-
The
reason
a phenomena called
frequency
These
can result
behind
If
aliasing.
components greater
falsely
translated
application of the
a signal
than fs/2
frequency
components and will corrupt
is
Sampling
sampled slower
will
be 'folded
frequency
c)
Figure
A- 7:
The
effect
in the time domain
into the
themselves
content of
a)
elimination of
than the Nyquist rate, those
over'
components will alias
the original
theorem is the
the
original passband.
as
lower
frequency
signal.
Actual input
Assumed input
of a non-integer number of cycles
in
a sinusoid
signal.
Spectral Leakage.
of cycles
for
all of
its
A
component
does occur, due to the
resulting
frequency
sampled
may
[19]. This
caused
by
not
necessarily
frequencies due to the finite
periodic nature of
amplitude results
components
signal
the
effect
the sharp
DFT,
as
in the
an
leakage
integer
number
length. When this
record
a smearing-out
is known
peak
possess
of
and
the energy in the
is due to the high
'replicated'
signal,
as
the DFT
APPENDIX A
sees
it,
in the
as
91
input
assumed
to abasing
in Figure A-7.
shown
which
Leakage
can
criteria.
Figure A-8-a
cycles and
occur
Thus, leakage
signal.
results
even
in masking
with
shows
Figure A-8-b
These sharp
a
a
shows
peaks
contain
can give
lines
frequency
false
frequency
that
signal
information
similar
components.
meets
the Nyquist
sine wave with a non-integer number of
mono-frequency
affect
spectral
of actual
properly band-limited
the
high frequency harmonics
leakage
creates
during
spectral analysis.
iltemLtime function
J?
^ftfTEMMTE ffnftlE!
)
3l1
PFJ
rvpdt* h*> n^wiivt*
MFTER Fl
\M>V* *CT p^rwJ<
I" t"*1*
W-W
O FY~T
Figure A-8: Leakage
'windowing'
effect of
recorded
for
simply from the
noise
in the
minimize
Random
Signal Noise.
being
effects
to
and
analysis.
For example, data
upon
the
collected
nt*4f!; iMth a
frequency domain
environmental
process
during
a
12-bit
are
noise
of noise
funcrrct
mono-frequency
sinusoid
a
is introduced into the digital
levels
resolution
introduced into
often
analog to digital
number of quantization
using
of a
-4<>%ic+
and
it.
An inherent level
quantization
is dependent
(vntr'u
gives
conversion.
applied
4096
to the
The
signal
potential
incoming
quantization
signal
signal.
levels. The
APPENDIX A
92
quantization noise
level is
in decibels from:
computed
Quantization Noise
A.3.2
Reducing
Aliasing.
Two
1.
Sampling
2.
Filtering
the
-20
log 4096
=
dB
-72.2
(A-15)
.
Spectral Abberations.
may be
precautions which
the
=
to
to
reduce
aliasing
faster than twice the Nyquist
signal at or
signal
used
eliminate or minimize
rate
frequency
are:
for that signal;
or
components greater
than
fs/2-
Filtering
can
be
dataset. Filters
Leakage.
1.
to sampling the analog
performed prior
will
be discussed
the
width of
the DFT (i.e. increase
2. Application
the high
of a
the data
reduce spectral
by increasing
window
the
leakage
which are:
number points used
in
duration);
record
effects of
to
employed
window, to taper the
frequency
the discrete
shortly.
Two techniques may be
Increasing
signal or afterward on
ends of
the sharp
peaks
the
sampled signal
in the
assumed
to zero,
input
signal
will reduce
(described
previously).
Figure A-9
peaks'
by
that
shows
effect
were evident
a smooth
Many
the
of
windowing in the time domain.
in Figure A-8
transition imparted
window
is derived from
types
a cosine
can
be
by
a
used
function
and
when
and
application of a window
to
may actually introduce the
signal
is duplicated in time,
'sharp
are replaced
windowing function.
but
is
a common
shown
1 /
The
the
Notice that the
a signal
type is the
here for TV
Hanning
window which
points:
2(n + 0.5)7r\
to
effects of
reduce
leakage
leakage for
total
signal power
components
that do have
will reduce
frequency
APPENDIX A
93
j a)
Actual
input
b) Assumed input
Window function
c)
dl Windowed input
Figure A-9: The
an
integer
a window
as
it
number of cycles
function to
could
be if there
a
Signal Noise.
tion
he
of a
were an
performed prior
Any filter
no smaller
signal.
to
intrinsic
Figure A-8-c
leakage.
integer
As
shows
The
the
spectral
number of cycles
in the
affect
'line'
of application
is
sinusoid
not
as
mentioned above
narrow
but the
is primarily
accomplished
for abasing reduction, this
or afterward on
the discrete time
by
to the sampling
'line'
applica
filtering
series
from Equation
levels). The
process and
is
reason
A- 15
(after substituting for
for this is that this
unremovable.
can
dataset.
reduce quantization noise should possess a stopband cutoff
value obtained
of
is clearly discernable.
of noise contamination
actual number of quantization
is
windowing in the time domain.
reduce
to data sampling
employed
that the
to
frequency
Reduction
filter to the
sampled.
signal
representing the dominant
effect of
level
'4096'
the
quantization noise
APPENDIX A
Signal
94
Filtering Techniques.
analog filters
and
Digital filters
data
after
A. 4
for anti-aliasing
used
of
frequency
in Section 2.4.2
algorithm.
one value
filters
used
for
signal processing:
are used with continuous-time
analog
discrete time
series.
a signal
to
series after
produce a
the discretization
process.
Use
before
and
(HRV)
de
and reduction of noise contamination
for
each point
Determination
Density
in the heart
components
processing this
entails
The FFT processing
signal analysis
results
in
a
is determination
of
the
dataset. The
conversion process
power spectral
frequencies in the
density
analyzed
is
signal,
not
by
to
signal
fast Fourier transform
or
array
of complex
However,
points).
processed
in the HRV
obtain
the
power
the
'power'
units, but
numbers;
rather as a
[30,
in
To this end,
a power spectral
contained
(FFT)
end purpose
signal.
Equation 12.7.5 in Press
expresses
in
a
variability
discrete dataset
spectral power
outlined
dataset
rate
by
signal
in the HRV dataset (4096
the Fourier transformed dataset is further
The
of
collection.
The detection
this
the discrete time
Power Spectral
scribed
to sampling
used prior
are used on
filters is widely
of
two types
are
digital filters. In-line analog filters
therefore
signals and are
There
density
p421].
in the
component
density
expressed
as
(Heart
Rate)
Hertz
As
a
density,
total
is
there is
no power at a single
power contained
obtained
limits
tion is
of
by
between
integration
the band. Since the
equivalent
to
37The frequency
=
1/T
where
the
actual
resolution
T is the
by
the
dataset is
frequency
record
length.
by
over some
and some
frequency
high
composed of
band. The
frequency filtgh,
density function between
the discrete
is determined
but
frequency, fiow,
power spectral
a summation of
subsequent multiplication
A/
of
low
some
frequency
the
frequency
discrete values, this integra
values contained within
the band
and
resolution37.
the inverse
of
the total length
of
the time
record
or
Appendix B
Rabbit Endotoxin
Methodology
from
Strong
a
Study
Grant Proposal
Results Sections
and
Grant Proposal to the
Children's Research Center
entitled
Heart Rate Power Spectrum
During
by
Septic
shock
principle
Brahm
and
Catecholamine Changes
in the Rabbit
investigator
Goldstein,
95
M.D.
STRONG CHILDREN'S RESEARCH CENTER GRANT
Heart Rate Pover Spectrum and Catecholamine Changes
Durina
Septic Shock In the Rabbit
Investigator:
Principal
Co-
Brahm Goldstein, M.D. (Pulmonology/Critical
Care)
Niels Lund, M.D.
Ph.D. (Anesthesiologyjcrltical Care)
Paul Woolf
M.D. (Endocrine-Metabolism
Unit)
Mark Kempski. Ph.D. (Mech.
Investigators:
,
Engineering, R.I.T.)
SPECIFIC AIM
The autonomic nervous system, composed of the
sympathetic nervous system and the
nervous system, is the principal
integrator of cardiovascular
homeostasis during stress. Pover spectrum analysis of
heart rate variability is a
parasympathetic
quantitative
proven,
noninvasive
measure
of
sympathetic
and
parasympathetic
Plasma catecholamine levels correlate with the degree of sympathetic
activation during sepsis.
We hypothesize that temporal changes in power spectrum
analysis of heart rate
variability and catecholamine levels predict the development
of autonomic failure and subsequent cardiovascular decompensation. The
model we
will use is E.
coll Induced septic shock in the rabbit. This information will define
the mechanism and timing of autonomic failure in septic shock. The significance for
medical care will be early prediction of cardiovascular collapse and a method of
monitor ins treatment
during septic shock.
Specific aim: To define heart rate pover spectrum and catecholamine changes as
a measure of autonomic failure in endotoxin-induced septic shock in the rabbit.
acvtivity.(l)
RATIONALE
Background
Septic shock Is a life-threatening complication of serious bacterial
infections.
Septic shock Is a major cause of irreversible hypotension, multiple
organ system dysfunction,
and death. Endotoxin is one of the principal bacterial
initiate the septic shock syndrome in gram-negative bacterial
is characterized by the development of cardiovascular
abnormalities including a high cardiac index,
low systemic vascular resistance
index, and myocardial dysfunction.
that
components
Septic
sepsis.
shock
Heart Rate Pover Spectrum Analysis
Power spectrum analysis of heart
measure
of
sympathetic
and
variability is
rate
parasympathetic
activity.
a
quantitative
(1-3) By
noninvasive
monitoring heart
rate
fluctuations In hemodynamic
?arameters can be performed. (1-3) Periodic fluctuations in heart rate occur at
owfrequencies (0.01-0. IS Hz) and at high-frequencies (0.25-1.00 Hz). The two
principle branches of autonomic cardiovascular control (the sympathetic and
?arasympathetic nervous systems) are reflected in heart rate power spectra by a
owfrequency peak around 0.01-0.15 Hz and a high-frequency peak around 0.25-1.00
Hz.
The low-frequency fluctuations are a result of heart rate variability due co
blood pressure fluctuations at this frequency. The lov-frequency fluctuations are
and
respiratory
mediated
by
rate
combined
quantative
variability,
and
sympathetic
analysis
parasympathetic
of
activity
at
rest
while
The
beta -sympathetic activity predominates during stressful conditions.
high-frequency fluctuations (>0.15 Hz) are under parasympathetic control and are
associated with HR variability as a result of the respiratory cycle (respiratory
sinus
arrhythmia)
.
(1-3)
has been used to evaluate autonomic function
heart failure, congenital heart disease, chronic
renal disease, diabetic peripheral neuropathy, mild hemorrhage, and brain
injury. (1-3) Heart rate power spectrum analysis is useful In the assessment of
Heart
in humans
spectrum
rate
pover
with
chronic
analysis
congestive
normal physiologic and pathophysiologic changes in the autonomic nervous system and
as a diagnostic and prognostic tool. (1-3) Patients with congestive heart failure
were found to demonstrate derangements in heart rate modulation at a frequency
diminished
with abnormal baroreceptor reflex responsiveness suggesting
but normal sympathetic cardiovascular tone. (2)
Experimental animal models Include the dog and rat. Pover spectra of arterial
blood pressure In spontaneously hypertensive rats indicate an Impaired control of
normotenslve controls. (3)
sympathetic drive to resistance vessels compared to
consistant
vagal
Brain Injury
Heart Rate Pover Spectrum and Catecholamine Data in Acute
Goldstein and Woolf are studying the relationship betveen plasma
Preliminary "suits in
pover spectrum changes.
catecholamine levels and heart
catecholamines reflect
control subjects and acutely brain Injured patients shov
low-^?^60^^6-"."",?^*^,?!?;?0^*
Preliminary
Drs.
.rate
sympathetic presynaptic activity while
postsynaptic sympathetic activity in the
Lov-frequency
absence
of
heart
rate
measurable
CatecechJlamines
activity during
are
acute,
power
changes
hemodynamic
th.
malor
stressful
cardiovascular
reflect
7em
Increased
fl"?"*"!*** *
sympathetic
activity
,,
a?5>the
In the
changes.
modulatory
situations.
substancesof
In
numerous
J^^USSLJT^^
species,
including man ana
plasma
rabbit,
catecholamine (norepinephrine, epinephrine, and dopamine)
correlate vith the degree of sympathetic activation
been demonstrated to
decapitation, head trauma, hypoxia,
sepsis,
levels have
during
While resting
and hemorrhage.
levels have been established In the rabbit, levels
during sepsis are
Dr. Woolf is an expert in the field of catecholamine research and will
insights into the association betveen catecholamines and
lov-frequency heart
catecholamine
unknown.
provide
pover.
rate
Hypothesis
We hypothesize that the hemodynamic changes
of
which
occur
shock
septic
during
the
development
are a result of failure of the autonomic nervous system to
for the cardiovascular abnormalities.
We propose that pover spectral
compensate
heart rate variability will provide a means to predict the development
failure and subsequent cardiovascular decompensation and shock in a
rabbit model of endotoxin-induced septic shock.
We will use heart rate pover
spectrum analysis to determine the mechanism and
timing of autonomic failure. We
use
plasma
will
catecholamine levels as a marker of sympathetic activation during
sepsis and correlate catecholamine
levels vith heart rate pover spectrum analysis
determinations, specifically lov-frequency pover. a measure of sympathetic activity.
tfe will test the efficacy of pover spectral analysis in
monitoring the autonomic
response to a therapeutic infusion of an exogenous
catecholamine, dobutamine, once
shock and hypotension have developed.
of
analysis
of
autonomic
The Rabbit Model
The rabbit is
a veil established model for the
study of endotoxin-induced septic
ideal model for our study. Dr. Lund has previous experience vith
this model (4), and is
currently using a similar model to study tissue F02 levels
during septic shock. We have validated the technique of pover spectral analysis in
the rabbit model in Dr. Lund's laboratory (see Fig. 1). The rabbit is large enough
shock
co
(4)
and
an
accomodate
arterial,
central venous and pulmonary artery catheters which will
physiologic monitoring. In addition, we will collect systemic
arterial, pulmonary arterial, and central venous pressure data for future pover
spectral analysis as Dr. Kempski develops the necessary algorithms and software for
pressure waveform analysis. This data will provide additional understanding of
cardiovascular control mechanisms such as ventricular-vascular
coupling and
autonomic control of the pulmonary circulation and form the basis for future
provide
adequate
Investigations and funding.
We will use an acute model of septicemia rather than a more protracted model
such as cecal ligation and perforation. This model provides for a clear and rapid
demarcation betveen baseline measurements and the development of sepsis and shock.
We chose to evaluate pharmacologic intervention vith dobutamine (a strong
beta-1, veak beta -2 and very veak alpha agonist) for tvo reasons. The first is the
dobutamine corresponds to the parameters that pover spectrum
been demonstrated to measure, i.e. beta- sympathetic activity. Secondly,
dobutamine is commonly employed in the care of critically ill patients vith sepsis
c
5
syndrome and septic shock. We vill administer dobutamine at tvo concentrations ,
tncg/kg/mln and 20 mcg/kg/mln at the onset of significant hypotension (blood pressure
decrease to > 2 standard deviations from baseline). These concentrations correspond
mechanism of
analysis has
action of
.
.
*-...
.
,--
.
-~
low and moderately-high clinical dosages, respectively.
We are currently generating heart rate pover spectrum data using the methodology
described belov. The rabbit has been validated as a model for heart rate pover
spectrum analysis in Dr. Lund's laboratory (catecholamine levels are pending). The
co
methodology
rat.
(1-3)
i
-a*
of
validation
Dnder
is
similar
pentobarbital
to
that
anesthesia
previously
i
-r
in the human,
used
(see METHODS) heart
.as
rate
spectral
dog,
and
analysis
^
cT-ta
tnf
!-:
r^te'i
.a^Mt^.fo
.1
rtaTf*Cf
raniUCT
Fig.
I
LA
Fig.
<
IB
C
i.a*
-p
.
.'r
-..4-
mcaiicMcv
Fig.
(Ht.tn
1C
performed on 5 normal adult rabbits [Fig. 1. Pover spectral
density (PSD)
(beacs/min 2/Hz) (y-axis) plotted vs. frequency (Hz) (x-axis)]. Figure 1A
demonstrates a pover spectral
plot
a
normal
in
anesthetized adult rabbit.
density
12,r f roqizency pover (LFP) at 0.010-0.15 Hz and the
high-frequency pover (HFP) at
Jng
0.25-0.50 Hz (the respiratory sinus arrythmia) are labelled. Pharmacologic blockade
of first the parasympathetic and then sympathetic nervous system vas done with
atropine (0.01 mg/kg) and atropine ? propanolol (1 mg/kg). The pover spectral
was
plots shov ablation
density
(Fig. IB). High- and
complete
autonomic
of high-frequency pover after atropine administration
lov-frequency pover are essentially totally ablated after
blockade
vith
atropine
and
propanolol
(Fig.
1C)
.
METHODS OF PROCgDimg
A.
Model
A total of 20 Nev Zealand vhite adult rabbits vill be studied (10 control/sham
Injection vith saline and 10 septlc/E. coll endotoxin Injection). Weight will be
between 2.7-3.1 kg. Male rabbits will be used to exclude any sex specific
differences.
B.
General subject assessment and management
All medications and their type, amount and frequency of administration are
recorded. Figure 2 shows the timeline of the study. Pentobarbital, a short acting
barbiturate, will be used for Induction and maintainence of anesthesia.
Pentobarbital is a myocardial depressant and will result in a moderate increase in
cardiac sympathetic tone. This will not interfere vith spectral analysis or
catecholamine determinations as the degree of sympathetic stimulation is
Insignificant compared to septic shock. Maintainence anesthesia vill be via
administration of intravenous pentobarbital 5 mg/kg iv q 20-30 min prn tachycardia
or agitation. Euthanasia is performed at the conclusion of the experiment as the
animals
are
not
expected
to
survive
the
septic
shock.
C.
Data Collection
All data are collected and compiled on standardized forms for data entry
(Appendix A).
Clinical data include age and veight. Cardiopulmonary data (heart
rate, respiratory rate, blood pressure, central venous pressure, pulmonary arterial
pressures), catecholamine levels, and heart rate pover spectrum data vill be
recorded at time 0 and then q 5 minutes until the development of hypotension
(average 20-30 minutes or 4-6 recordings). These measurements vill be repeated
infusion of 5 mcg/kg/mln and then
during dobutamine infusions, once 5 minutes after
5 minutes after the dobutamine is increased to 20 mcg/kg/mln. (See timeline diagram
in Fig. 2). EKG, respirations, and arterial/venous pressure data vill be stored on
44 megabyte Bernoulli cartridges. Pover spectra vill be processed and analyzed at
che
conclusion
of
the
experiment.
D.
Catecholamine Levels
Serum catecholamine are dravn from indvelllng venous catheters. Handling and
Dr. Woolf. (5) Dobutamine infusion
assay of samples have been previously described by
pressure liquid
will not Interfere vith epinepherine or norepinephrine high
dobutamine infusions are inna curate
chromatography assays. Dopamine assays during
personal communication)
and vill not be run. (ref.
-
Flguro 2.
Tinlin
VIVARIUM
of
study.
EQUILIBRATION
INDUCT
ANESTHESIA
(PENTOBARB
IS MG/KG IH)
VIVARIUM
BASELINE
MEASUREMENTS
(VITAL SIGNS,
PSA,
INJECT NaCl/
ENDOTOXIN
CATECHOLS)
HYPOTENSION
(BP DEC
>
(L3137
1.5 MG/KG)
-130
-110
TIME
(MIN)
-95
-33
-S
0
EUTHANASIA
(PENTOBARB
16S MG/KG)
65
DOBUTAMINE S MCG/KG/HR X 5 MIN THEN
20 MCG/KG/MIN X S MIN
ANIMAL PREP.
(IV, TRACHEOTOMY,
ARTERIAL/ CVP/ PA
CATHETERS)
2SD)
CONTINUOUS MEASUREMENTS Q 3 MIN
THROUGH DOBUTAMINE INFUSION (VITAL SIGNS,
CATECHOLS)
E.
Pover Spectral Analysis
We use a modification of the
methodology described by Akselrod et al (3) and
developed by Drs. Goldstein and Kempski. The instantaneous heart rate and
rate
are
recorded from a standard lead II EKG using Hevlett Packard
respiratory
Monitors models 78213C and 78212D and collected for 256 sec. Data are collected and
analyzed using an AST Premium 386/25 PC in conjunction vith a Data Translation
2801A
data acquisition board vith sampling at 1 kHz. EKG R waves are detected and a
nominal 256 sec instantaneous heart rate time series is constructed. A heart race
variability dataset is obtained by subtracting the average heart rate from the
instantanteous heart rate followed by linear interpolation. The heart rate
variability dataset is passed through a Blackman lov-pass filter (5 Hz) and a
Hanning vindov to produce the pover spectra using a modified Asyst Data Acquisition
and Analysis Package. The integrated spectral
density (area) and peak amplitude
symmetric about the respiratory frequency, usually 0.25-0.40 Hz in man and 0.25-1.0
Hz in the rabbit, are used as a measure of
parasympathetically mediated respiratory
sinus arrhythmia. The density and peak amplitude around 0.01-0.15 Hz are used to
quantify beta-sympathetic mediated HR fluctuations.
F.
Statistical Analysis
The data base are managed using INGRES software running on a VAX cluster
computer system of the University of Rochester Computing Center. The primary
database is downloaded and managed in SAS after transferral to a VAX 8350 owned by
the Division of Biostatistics. Stastlcal methods that are useful Include analysis
of variance and multiple linear and logistic regression. Subjects are studied
Longitudinally. Changes in vital sign* and cardiovascular parameters (as described
in parts B and C) are correlated with catecholamine levels and power spectrum data
and are used to determine he
specificity and sensitivity of these measures. We
expect to observe an Increase between 50% and 1000X in lov-frequency pover meesures
during the development of septic shock and hypotension. During treatment vith
dobutamine, we expect the lov-frequency pover to decrease proportionately with a
return towards normotension. For longitudinal studies, repeated measures of analysis
of variance and covariance are used. Statistical analysis of pover spectrum data are
performed as described by Shannon et al.(l)
SIGNIFICANCE OF THE RESEARCH
This project is a unique collaboration of medical scientists from Pediatrics
(Dr. Goldstein), Anesthesia (Dr. Lund). Medicine (Dr. Woolf) and Engineering (Dr.
Kempski). Each has extensive experience in their own field. Preliminary data assure
successful
These
pover
completion
studies
spectra
and
vill
these
protocols.
provide
pioneering
of
catecholamine
levels
data
vith
the
by
correlating changes
development of septic
in heart
in
shock
race
the
These data vill provide understanding of the mechanism and timing of
autonomic failure during the development of septic shock. We predict pover spectral
analysis of heart rate variability vill enable us to assess the development of
autonomic failure and cardiovascular decompensation prior to the onset of any
measurable hemodynamic changes* If this technique proves valid, then early
therapeutic intervention based upon pover spectral data vith fluids or vasoactive
agents may prevent or ameliorate the development of septic shock, hypotension, and
multiple organ system failure.
The data obtained from this study vill be preliminary data for grants to the
American Heart Association and the NIH (Biomedical Research Technology Grant). We
believe this research vill lead to therapeutic interventions in patients vith
autonomic failure and reduce morbidity and mortality.
rabbit.
,
REFERENCES:
L.
2.
3.
4.
5.
Shannon DC. Carley DW. Benson H.
Physiol 1987; 253:H874-H877.
Akselrod S, Ellash S, Orna 0, et
Aging
of
modulation
Hemodynamic
al.
of
heart rate.
regulation
Am J
in SHR:
inv?sU8*Slon by "Pc"l analysts.
Am J Physiol 1987; 253:H176-H183.
Saul J?, Yutaka A, Berger RD, et al.
Assessment of autonomic regulation in
heart failure by heart rate spectral
analysis.
Am J Card
f-fS"1?,
c?582sFrIS
r
1988; 61:1292-1299.
Guiterrez G. Lund N, Pallzas F. Rabbit skeletal muscle p02 during hypodynamic
sepsis.
Chest 1991 (accepted).
Woolf PD, Hamil RW, Ue LA, et al.
The predictive value of catecholamines in
J Neurosurg 1987; 66:875-872.
assessing outcome in traumatic brain injury.
Appendix A
DATA ENTRY FORM
Heart Rate Pover Spectrum Changes During
Endotoxin Septic Shock in the Rabbit
Subject
Identification #:
Clinical Data:
Weight:
Age:
Data Collection on
/
:
(kg)
/
Time:
hypotension
infusions
of
and
minutes
then
5
min
(repeat q 5
5 and 20
after
min
dobutamine).
Cardiopulmonary data:
Heart
rata:
Respiratory
rate:
Blood pressure:
Central venous pressure:
Pulmonary
arterial
pressures
(PAP/PCWP)
:
Catecholamine levels :
Epinephrine:
Norepinephrine :
Dopamine :
Pover spectrum analysis:
Lov-frequency
pover
(0.01-0.15 Hz):
0.01-0.04 Hz
0.04-0.07 Hz
(0.15-1.0 Hz):
(0.01-1.0 Hz):
High-frequency
Total pover
HFP/LFP+HFP
LFP/LFP+HFP
pover
ratio:
ratio:
amplitude
area
area
amplitude
area
amplitude
area
amplitude
until
mcg/kg/mln
srea
Appendix C
Related Published Abstracts
1. Assessment
in
pediatric
2. Heart
rate
function
brain injury.
[14]
power
brain death.
3. The
of autonomic
injury
4. Heart
5. Heart
during
and
cardiovascular
brain death.
state
severe
brain
injury
and
in
children
following
severe
[16]
rate power spectral changes
rabbit.
in
changes
rate spectral analysis
[15]
autonomic
brain
spectrum
heart
by
during
endotoxin shock
in the
[17]
rate
power
spectrum
endotoxin shock
and
in the
plasma
rabbit.
101
[18]
catecholamine
changes
THE AMERICAN PEDIATRIC SOCIETY
1991
THE SOCIETY FOR PEDIATRIC RESEARCH
ABSTRACT FORM
ADDRESS
CORRESPONDENCE TO:
Brahm Goldstein,
Name
Box 667
Address
PRESENTATION FORMATS
ACCEPTABLE TO THE AUTHOR:
M.D.
(choc*
all
22465
Goldstein.
First Author:
B.
IWW.MU4
that apply)
URMC
Urn la EBgajte lor On.
Chaot
601 Elmwood Avenue
14642
Rochester, NY
x
of
Thaaa Awonto
All
Nohania Bowo Aonl In CarsloloBy
Poster Symposium
Feoow'a Boolo Raaeenol Amort
Poster
FoSoo/o CTlfilMl Billirit Award
Platform
Mm Omoor lliiiirr* Aart
(716) 275-6542
Telephone
N
Serial Number:
VWsseVjf HeWeVCan AMMfw
SUBSPECIALTY CHOICE
(Cheek
Only One)
OF AUTONOMIC FUNCTION BY HEART RATE SPECTRAL ANALYSIS
IN PEDIATRIC BRAIN INJURY
Donna
DeKing
Kempski
David
Mark
Brahm
DeLong
Goldstein.
(Spons. by Edward B. Clark). Univ.
Christopher Cox. Paul D. Woolf
of
of
Rochester School of Medicine , Strong Memorial Hosp , Depts
Rochester
and
and
Rochester,
NY,
Medicine,
Neurology,
Feds,
ASSESSMENT
flrlnlaara.nl Medicine
Behavioral Pediatrics
X
.
.
.
Cardiology
.
.
.
Critical Can
Developmental
Biology
Devetopfliental
Pharmacology
___
Dyaoiorphology
4
Institute of Technology
autonomic
associated
with
cardiovascular
is
Brain
injury
dysfunction. Low-frequency (0.01-0.15 Hz), high-frequency (0.15-0.5
Hz) and total heart rate spectral power (0.01-0.5 Hz) are measures
Teratology
of
flaaliiiaiileiiilinn 4
He
outcome.
patient
injury (7M, 5F) (mean
12
8.9+5.9
studied
age
ICU.
Pediatric
the
to
admitted
with
correlates
analysis
spectral
and
brain
with
0.1-16)
range
years,
Pediatric Education
by heart
brain
injury
patients
consecutive
hypothesized
rate
of
severity
General Pediatric* 4
We
respectively.
measured
as
Nutrition
parasympathetic, and total autonomic
that autonomic dysfunction
sympathetic,
cardiovascular
activity,
Preventive Pediatrics
-
Admitting
head + multiple trauma (n-3),
rate
Heart
hemorrhage
intracranial
and
anoxia
(n-2)
(n-2),
Glasgow
Coma
Score (GCS) were obtained on
and
analysis
spectral
days 1,2,3 and weekly thereafter. Glasgow Outcome Score (GOS) was
diagnoses
head
were:
(n-5),
trauma
.
Hematology
4
Oncology
laununoiogy
recorded
Infsctlous Dtsoeooo
Mstahoflsia 4 Diabetes
Neonatology
Neonatal
*
with
Qonoral
follows:
(n-4)
We
.
We compared
data.
Data
GOS
GCS,
and
patient
analyzed
were
using
Pearson correlation coefficient, logistic
GOS were as
Poisson regression (GOS).
and
analysis
recovery
(n-5),
found
(n-0)
persistant
direct
a
state
vegetative
between
correlation
(n-2)
(n-l), and
disability
moderate
,
,
day 1
GCS
severe
and
death
both
(r-0.79, p-0.03) and total (r-0.79, p-0.002) power.
maximum
of
levels
low-frequency and maximum total power
(p-0.03).
the study were associated with increased survival
levels of maximum low-frequency power were associated with
and
power
related
total
(p-0.05).
Thus, low-frequency
GOS
low-frequency
lateiunology
Higher
41
during
Higher
better
Neonatal Nutrition
4 Metabolism
Naonatal
good
disability
Epidemiology
Follow-up
Neonatal
(survival),
regression
Cardiology
discharge.
spectral
deviation,
mean+standard
Naonetal
4
hospital
upon
survival
directly
with
Pulmonology
to
of
severity
injury
neurologic
in
outcome
and
children
brain Injury.
Nephrology
Neurology
Pulmonology
Sponsoring
Type Name
or
Author Member:
Signature
with abstract typed within tha
Abstract Submission Fss
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penalty).
1991
ABSTRACT OF PAPER
List name, address & phone
Presenter
number of
Brahm
Goldstein, M.D.
Box 667
University
of
Rochester
Medical Center
601
RlmunnH
HEART RATE POWER SPECTRUM CHANGES IN SEVERE BRAIN
INJURY AND BRAIN DEATH
Brahm Goldstein, MD, FAAP, Mark H. Kempski, PhD*, David J. DeLong*, Donna E.
DeKing, Christopher Cox, PhD, Paul D. Woolf, MD, Univ. Rochester Medical
(Center, Rochester, NY 14642 and 'Rochester Institute of Technology, Dept. Mech.
Engr.
Avpnnp
14642
Rochester, NT
716-275-6542
S Academy Fellow
? Resident Fellow
D
Resident Non-member
?
Non-member
INTRODUCTION: Brain injury is associated with cardiovascular autonomic dys
function. Very low-frequency power (0.01-0.04 Hz) and mid low-frequency power
(0.04-0.07 Hz) are measures of cardiovascular sympathetic activity while high-fre
quency power (0.15-1.0 Hz) measures parasympathetic activity. We hypothesized
autonomic cardiovascular activity, as measured by heart rate power spectral anal
ysis, was decreased in patients with brain death compared to those patients with
severe brain injury but not brain dead.
METHODS: We analyzed heart rate power spectra in 4 brain dead patients and
compared the results to 4 patients with Glasgow Coma Scale < 6. Heart rate, respi
ratory rate, blood pressure and power spectral data were recorded. We performed
cold pressor testing on the brain dead patents to evaluate the autonomic cardio
vascular response. Cold pressor testing was performed by ice-water immersion of
lone hand for 4 minutes with vital signs and power spectral data recorded during
the last 2 min. of immersion. Data were analyzed using mean, standard deviation,
and paired t-tests.
Presentation
3"'
GCS
Projector
VHSVs"
%-
BETA
? Proiectlonist
?
are expressed as mean (+ standard
2x2 Slides
D Overhead
?
RESULTS: Data
will need:
147(33)
148(32)
Reap,
19 (8)
13
(4)
13
(4)
86 (7)
74
(27)
70
(26)
rate
(per min)
preaaure
power
Box 93
Boston, MA 02111
low-frequency
power
<bpm2/Hz)
00813
(00881)
(bpm2/Hz)
High-frequency
.01499
(02438)
(bpm2/Hz)
MM
power
00995
(.00718)
DEADLINE
Mav
15,
1991
presaor
00020
00015
(.00018)
(00019)
.00001
(.00001)
.00133
(.00225)
00001
(.00001)
00130
(00224)
Patients with GCS = 4-6 had very low- and mid low-frequency power spectral val
2-4 orders of magnitude greater than brain dead patents. Patients with GCS =
3 had values one order of magnitude greater than brain dead values. Cold pressor
testng in brain dead patents resulted in no change in power spectral values.
CONCLUSION: Brain death results in near undetectable levels of very low- and
mid low-frequency heart rate power. There is a significant difference in autonomic
cardiovascular actvity between patents with severe brain injury and brain death.
There is no autonomic cardiovascular response to cold pressor testng in brain
low- and mid
death. Thus, near undetectable values of very
low-frequency heart
rate power in conjuncton with cold pressor testng may prove to be a reliable diag
ues
IMPORTANT
? cold
Hg)
Very low-frequency
Kristan M. Outwater, MD
New England Medical
Center Hospitals
750 Washington Street
Brain death
117(23)
(mm
Send to:
deviation).
Brain death
Heart rate (bpm)
Mean blood
Other
<
nostic test for brain death.
THE AUTONOMIC CARDIOVASCULAR STATE IN CHILDREN FOLLOWING
BRAIN INJURY AND BRAIN DEATH
Brahm Goldstein, MD, Donna E DeKing, David J DeLong, Mark H Kempski, PhD, Christopher
Cox, PhD, Mary M Kelly, RN, Diane D Nichols, Paul D Woolf, MD. Univ. of Rochester School
of Medicine and DepL of Mech. Eng., Rochester Inst, of Tech.
INTRODUCTION: Brain injury is associated with autonomic cardiovascular dysfunction. Brain
death results in complete cessation of efferent autonomic impulses from the central nervous sys
tem. We hypothesized that autonomic cardiovascular activity, as measured
by heart rate power
spectrum analysis
test
(CPT),
with severe
heart rate
(PSA),
plasma norepinephrine
(NE) levels, and the response to the cold pressor
be decreased or absent in patients with brain death when compared to patients
brain injury. Low-frequency heart rate power (0.01-0.15 Hz) and high-frequency
would
power
parasympathetic
(0.15-1
Hz) were measured as parameters of cardiovascular sympathetic and
activity, respectively.
METHODS: We analyzed cardiorespiratory parameters, PSA, NE, and response to CPT in 6
brain dead and 3 patients with Glasgow Coma Scale (GCS) < 6. HR, RR, BP, PSA, and NE lev
els were recorded. The CPT was performed by ice- water immersion of one hand for 4 min. with
vital signs, PSA, and NE obtained
during the last 2 min. Data were analyzed using mean, SD, log
transformation, paired and unpaired t-tests, Mann-Whitney and Signed Rank tests.
RESULTS:
GCS
<
GCS
6
+
N
3
Age (years)
3.6 3.7
HR (bpm)
132 + 49
RR (per min)
32 15
Mean Blood Pressuire 88 26
(mm Hg)
power
0.00603a
High-frequency
power
(bpm^)
0.00150
422 lb
Norepinephrine
(pg/ml)
Data
are expressed as mean +_
SD.
cold
pressor
6
6
5.1
+7.2
-
133+48
38+13
88 30
137 36
17 + 8
67 24
137 + 37
17 + 8
65 22
0.03486
0.00022a
0.00024
0.02117
0.00011
0.00017
0.00573
0.00097a
0.00251
0.00183
4318
103
a
p
<
0.0001
(n
0.00097
=
0.00181
135
3)
52
28
5542
5181
Brain death
+
-
0.08442
(bpm^)
pressor
3
0.06463a
Low-frequency
Brain death
6
<
cold
b
p
<
0.05
lowfrequency power (LFP). CPT in GCS < 6 patients
overlap between groups at
20-100% different from baseline values although
were
LFP
that
RR
and
in
resulted in changes
not statistically significant. CPT in brain dead patients resulted in no measurable change in car
<
diorespiratory parameters or PSA. The absolute changes with CPT were greater in GCS 6 pa
<
patients
than
brain
death.
6
greater
in
GCS
tients compared to brain death. NE was significandy
group.
either
in
CPT
after
There were no significant changes in NE levels
There
was no
CONCLUSIONS:
1 Brain death
NE.
results
.
j
in
abolition of
ji
,
r
low-frequency heart rate power as well as reduced levels of
.
2. There is no autonomic cardiovascular response to the cold pressor test in brain death.
3. There is a significant difference in autonomic cardiovascular activity between patients with
severe
4. Thus,
brain
injury and brain death.
near undetectable values of
pressor test
may prove to be
low-frequency heart rate power in conjunction with the cold
a reliable
diagnostic test for brain death.
HEART RATE POWER SPECTRUM CHANGES DURING ENDOTOXIN SHOCK
IN THE RABBIT
Brahm Goldstein, MD, Doris R Stair, Richard deAsla, Donna E DeKing, David J DeLong, Mark
H Kempski, PhD, Niels Lund, MD, PhD, Paul D Woolf, MD. Depts of Ped, Anesth, and Med,
Univ of Rochester School of Medicine and Dept of Mech Eng, Rochester Institute of Technology
INTRODUCTION: Septic shock is associated with severe hypotension and autonomic cardio
vascular dysfunction.
Low-frequency heart rate power (LFP)(0.01-0.15 Hz) and high-frequency
heart rate power (HFP)(0. 15-2.0 Hz) are measures of cardiovascular sympathetic and parasympa
We hypothesized that temporal changes in heart rate power spectrum
(HR PSA) may correlate with the development of autonomic failure and subsequent car
diovascular decompensation in a rabbit model of septic shock.
METHODS: We studied HR PSA in 9 anesthetized adult male New Zealand White rabbits (6
septic, 3 control). After tracheostomy, internal jugular and carotid artery cathetization, animals
were maintained on
FIO2 = 0.40. There was a 30 minute equilibration period prior to each experi
thetic activity, respectively.
analysis
Baseline HR, RR, mean arterial pressure (MAP), and HR PSA were obtained. Septic
induced by E.Coli endotoxin 1.5 mg/kg iv over 6 min. Controls received 1.5 ml/kg
saline. Data were recorded semicontinuously until the onset of severe hypotension (MAP < 65 mm
Hg). Dobutamine was then infused at 5 and 20 mcg/kg/min for 10 minutes each. Data were ana
lyzed using mean, standard deviation, and t-tests.
ment.
shock was
RESULTS: Baseline HFP was greater than LFP (mean HFP = 0.0524 0.0692 bpm2, mean
LFP = 0.01 120.0102, p=0.05). There was no difference in baseline cardiorespiratory or HR
PSA measurements between endotoxin and control groups. LFP and MAP remained stable (
15%) for > 60 minutes in controls; HFP was variable. After endotoxin, LFP decreased (mean A
LFP = 0.00450.0067 bpm2. p = 0.03) with a concomitant decrease in MAP (mean A MAP =
21.5+.1 1. 1 mm Hg p < 0.003) in 6/6 septic rabbits. Dobutamine increased LFP and MAP in
log
,
endotoxin treated
(mean A LFP
=
0.0467+0.0528 bpm2,
mean
A MAP
=
15+17
mm
Hg) and con
trol (mean A LFP
0.08510.0917 bpm2, mean A MAP 2618 mm Hg) rabbits. There was an
inverse relationship between LFP and HFP in 3/3 control and 5/6 septic rabbits. Data from endo
toxin treated rabbit #1 are shown in Figures.
=
=
M
S
a
^ \
ENDOTOXIN
fc 0
1
o*
-id
\/t
u
z
Y
DOBUTAMINE
CONCLUSIONS:
1
.
After the
administration of
endotoxin, a decrease
in MAP along with
dicate impending severe hypotension and shock.
2. The baroreceptor reflex remained intact during endotoxin
shock.
a
decrease in LFP may in
However, the relationship be
inverse of normal, i.e. as
activity
parasympathetic increased.
while
decreased
hypotension developed,
3. Although not statistically significant, dobutamine tended to increase MAP and LFP in controls
to a greater extent than in endotoxin treated rabbits.
4. These results are best explained by inhibition or blockade of beta-sympathetic cardiac receptors,
tween cardiovascular sympathetic and parasympathetic
was the
sympathetic response
or
decreased release of catecholamines during the development of endotoxin
shock.
THE AMERICAN PEDIATRIC SOCIETY
THE SOCIETY FOR PEDIATRIC RESEARCH
1992
N
ABSTRACT FORM
WDrot uumeitomkke re
Brahm
(Ual Nhw InUalal
PRESENTATION FORMATS ACCEPTABLE
Slnjet, CKv, State Zip)
Pediatric Critical Care
Umveristy
of
Rochester,
NY 14642
B
Goldstein.
First Author
Goldstein, M.D.
Address (Dapi.. Institution,
33402
Serial Number
fcheck
Rochester Medical School
601 Elmwood Ave
all
Out tpply)
1
All
Poster Symposia
Postar
T...Dhon.(
275-8138
716i
Subspecialty Platform
SUBSPECIALTY CHOICE
(Chock
MUST BE RECEIVED BY:
January 3,
199
Only One)
Adolescent Medicine
HEART RATE POWER SPECTRUM AND PLASMA CATECHOLAMINE CHANGES DURING
ENDOTOXIN SHOCK IN THE RABBIT.
Behavioral Pediatric*
__
Cardiology
Brahm Goldstein. Doris R Stair. Richard deAsla. Donna E DeKing. David J DeLong. MaricH
Clinical Bloethica
Kempski. Rebecca B Tipton. Niels Lund. P;n|l D Woolf (Sports, by Harvey Cohen). Depts of Ped,
Anesth, and Med. Univ of Rochester School of Medicine and Dept of Mech Eng, Roch Inst of Tech.
Critical Car*
Developmental
Biology
Developmental
Pharmaoology
___
_^
Dysmorphology
4
Septic shock is associated with hypotension and autonomic cardiovascular dysfunction. Low-fre
quency (LFP)(0.01-0.15
Teratology
Endocrinology
Epidemiology
power spectra and plasma norepinepherine
4
anesthetized adult male
Preventive Pediatric*
internal jugular cannulation and tra
for 60 min. (controls) or until mean arterial pressure (MAP) decreased > 20 mm Hg. Data
using mean, SD, log transformation and t-tests. After endotoxin, MAP and LFP de
creased but catecholamines were unchanged. HFP decreased with in both groups.
*
Control (N = 4)
Endotoxins = 6)
p < 0.05
60 min.
Dec. MAP>20 mm Hg
Basal
were analyzed
Pediatric Education
Genetlca
Hematology 4 Oncology
Immunology
Infectious Disease*
Metabolism 4 Diabetes
HR(bpm)
146
MAP (mm
85+5
Hg)
Log LFP (BPMA2)
Gsnsral
Epidemiology
4 Follow-up
Neonatal Immunology
179
+-13
77
18*
+
0.89
-4.13
+
-2.78+
1.16
-5.40
+
92
+
111
40
159
2
+
+
-4.78
LogHFP(BPMA2)
NE (pg/ml)
EPI (pg/ml)
DA (pg/ml)
Neonatal Cardiology
Neonatal
(NE), epinepherine (EPI). and dopamine (DA) levels in 10
min. after carotid and
recorded
General Pediatries 4
-
NZW rabbits. 30
activity, respectively. We studied changes in heart rate
cheostomy, E. coli endotoxin (1.5 mg/kg) or saline (1.5 ml/kg) was infused over 6 min. Data were
Gastroenterology 4 Nutrition
Neonatology
Hz) and high-frequency heart rate power (HFP)(0. 15-2.0 Hz) measure cardio
vascular sympathetic and parasympathetic
82
0.724
0.97*
+45
224
62+
0.93
-3.90 + 0.90
127+118
-4.85
+ 35*
20
7
+
+
+
21+0
21+0
28+
17
41+0
54+16
50+
22
5*
1.98*
-6.35
+
-5.33
+ 0.73*
114+ 91
26+8
66+59
We conclude that after endotoxin administration a decrease in MAP and LFP with no increase in cate
cholamines indicates impending shock. We suggest that inhibition of sympathetic nervous system ac
4 Hematology
Neonatal Infectious Olssssss
tivation
Neonatal Nutrition
by
endotoxin
contributes, at least
in part, to the development
of endotoxin shock.
4 Metabolism
Neonatal
Pulmonology
Nephrology
Neurology
Pulmonology
Sponsoring or
Tvps Name
Author Member
Signature
WTUHH) RtStARCT 8TMHBW WITH UniUOIUP
These Joint Saaaiorta will ba hald on Monday afternoon. May 4. 1992. If
you want your abstract to
you must
ba
eonaidarad
for any
of tha
following
sessions,
H*j
Check if
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accompanied
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eligible
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Cardiology
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Differentiation
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APS/SPR Prooram Office. P.O. Box 675. 141
Appendix D
Sample Program Output for
107
a
Normal Analysis
EKG Waveform Analysis
/ Heart Rate Variability Study
02/17/92
13:17:33
FILE
Original
File
Data
File
Name:
:
Results
COMMENTS
RS15-13.DA
Comments:
1>
HR153
RR26
BP84/68(77)
CVP4
2>
3>
4>
5>
6>
7>
8>
#Chnls
4
File:
RS15-13.DAT
SEARCH
File
Subfile
Size:
Scan Window
Size:
Windows
Subfile:
per
Zoom Window
Q-R-S
Complex
Maximum
Peak
Maximum
Instantanous
Digital
Smoothing
Voltage
Threshold:
cutoff
Total R-peaks Accepted:
Average Heart Rate:
Total Record Time [R to
Total
resolvable
Removed
IHR
***
8
Points
Intervals
Points
2.70000
R]
Points
BPM
15.99076
(IHR. VALUES
668
IHR Values
array)
Removed
***
BPM
Hertz
152.33060
.00781
detected
Milliseconds
326
128.07401
:
Time:
(msec)
(msec)
(msec)
(msec)
Volts
RESULTS
Frequency:
R-peaks
NO
Points
5.00000
frequency:
Frequency:
original
Points
128
468.75000
Heart Rate:
ANALYSIS
Nyquist
1024
128.00000
Proximity:
08/01/91
CRITERIA
95
Size:
Minimum
Smallest
Date:
Seconds
Hertz
Hertz
Points
12:01
Band Number:
Band
Name:
Lower
Edge
Frequency:
Upper
Edge
Band
PEAK
Frequency:
Frequency:
Band
PEAK
Value
Band
PEAK
.01562
.03904
.01562
.21818
Power
Band TOTAL Power
Band Number:
Lower
Band
VLFP
,00170
,00425
Name:
Hertz
Hertz
Hertz
(actual)
(actual)
Frequency:
04 68 5
Hertz
Frequency:
,06246
Hertz
Band
PEAK
Frequency:
04685
Hertz
Band
PEAK
Value
11526
BPM"2/Hertz
Band
PEAK
Number:
Band
Name:
.00090
BPM"2
.00148
BPM*2
(actual)
(actual)
Lower
Edge
Frequency:
.01562
Hertz
Edge
Frequency:
.14835
Hertz
Band
PEAK
Frequency:
.01562
Hertz
Band
PEAK
Value
.21818
BPM*2/Hertz
Band
PEAK
Power
.00170
BPM*2
Band
TOTAL
Power
.00832
BPM~2
Number:
Band Name:
HFP
Hertz
Edge
Frequency:
.15616
Frequency:
.49971
Hertz
.46848
Hertz
Band
PEAK
Frequency:
Band
PEAK
Value
1.04970
Band
PEAK
Power
.00820
BPM"2
Band
TOTAL
Power
.04840
BPM'2
Band Number:
Band
Name:
,07000
Hertz
Hertz
(ideal)
(ideal)
HFP
(actual)
(actual)
01000
Hertz
15000
Hertz
(ideal)
(ideal)
(actual)
(actual)
15000
Hertz
50000
Hertz
.15000
Hertz
2.00000
Hertz
(ideal)
(ideal)
BPM"2/Hertz
15-200
Lower
Edge
Frequency:
.15616
Hertz
Upper
Edge
Frequency:
1.99884
Hertz
Band
PEAK
Frequency:
.46848
Hertz
Band
PEAK
Value
Band
PEAK
Power
.00820
BPM"2
Power
.07404
BPM~2
Band TOTAL
.04000
15-50
Upper Edge
Lower
(ideal)
(ideal)
LFP
Upper
Band
Hertz
MLFP
Edge
Band
Hertz
.04000
BPM~2/Hertz
BPM*2
BPM"2
Upper Edge
Power
Band TOTAL Power
.01000
1.04970
(actual)
(actual)
BPM*2/Hertz
(ideal)
(ideal)
Band Number:
11
Band Name:
SPECTRUM
Lower
Edge
Frequency:
.00781
Upper
Edge
Frequency:
15.99076
Spectrum
PEAK
Frequency:
.46848
Spectrum
PEAK
Value
PEAK
Power
Spectrum TOTAL Power
Spectrum
1.04970
Hertz
Hertz
Hertz
(actual)
(actual)
Listing
Hertz
Hertz
(ideal)
(ideal)
BPM~2/Hertz
.00820
BPM~2
.08308
BPM~2
USER-DEFINED/List-Selected
Ratio
.00781
15.99076
Power
TOTAL:: TOTAL
Ratios
TOTAL
POWER
3:3+4
14671
.05672
4:3+4
85329
.05672
3:3 + 5
10104
.08236
5:3+5
89896
.08236
(denom.)
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*
Appendix E
Software Design
and
Program
115
Operating
Manual
CONTENTS
116
Contents
Appendix E
Local Table
Software Design
-
of
and
Program
Operating
Contents
Manual
115
116
Local List
of
Figures
117
Local List
of
Tables
118
E.l
ASYST Software Usage
119
E.2
The Program Format
120
E.2.1
The Original Program Format
120
E.2.2
The Final Program Format
121
E.2. 3
Program Source Code Development
E.3
The Menu-Interface
E.4
Using
E.5
Additional Features
Index
of
the Application Program
the Program for
of
and
a
Normal HRV Analysis
the Program
Layout
122
122
127
134
E.5.1
Graphics Environment Menus
135
E.5. 2
Supplemental Program Utilities
137
of
Operator's Manual
145
LIST OF FIGURES
List
of
E-l
An
117
Figures
Procedure Description Header. The line
example of a
the @
sign
%
the
with
lists those
routines
lists those
sign
that
this
call
E-2
listed separately
The Main Menu display of the
E-3
The Filename. Prompt Window
The
one.
this
routines which
beginning with
line(s) beginning
routine calls.
LIBSERVRs
123
called are
text.
The
particular
The File
as
running is Transfer Single
Channel,
127
comment
access
to
various
viewing
of
the
allows
line editing,
and
DOS
collected
128
Editor/ DOS Utilities Menu
allows
examination
the
of
data file. Comments lines in the datafile
comments
can
be
edited
129
necessary
The
Display Subfiles Contained Within
data file in the
previous
The
allows
menu
editing to
displays the
selection
the file
same window area where
The Edit File Comments
edit, then
E-9
shown
data file
a
and contents of a
E-8
routine
The DOS Utilities & Comment Editor Menu
data in
E-7
filenames. Note the
particular routine
commands, data file
E-6
of
from the Main Menu
selected
E-5
display
for entry
used
using the window is displayed in the title
bar. In this case, the Main Menu selection, Transfer Single Channel, is in use. 126
The Routine Processor Window has a vertical space of 12 lines to display
name of
E-4
the
124
application program
selection
The
proceed.
contents of
comments are
queries
a
comment
example shown
is
listed.
.
number
relates
the
.
to the
figure
Modify
131
Status-Comment-#8
stamped'
status
E-10 The GRAPHING
line in
a
menu
allows
adjustment
of
the 'time-
data files
menu allows
131
various options
for
plotted graphs:
printer
hard copy, comment insertion, and entry into the Multigraph environment.
The maximum frequency plotted can also be changed for spectral plots.
.
E-ll The Put Comment
Menu,
ation and placement of
E-12 The MultiGraph
the
selected
two
separate graph
menu allows
display
Directory Display
from the GRAPHING Menu
plotting
of
allows
labels
two
examination of
136
graphs of processed
data
on
137
allows
the files
lists the
requested
E-14 The Set Search Parameters
for the
listing by
a
drive
and allows
scrolling feature.
.
.
allows adjustment of several parameters
during
a vertical space of
138
140
during
data processing
Manual
The
E-16
Processing Commands
used
available space on a
window allows adjustment of several parameters
data processing
E-15 The Set Search Parameters window
used
135
cre
same
E-13 The
130
to
18 lines to
Menu, selected from the Main Menu, has
display additional menu items
141
143
118
LIST OF TABLES
List
E-l
of
Tables
Listing
of
descriptions,
tines in the
E-2
Main Menu
names and source
file locations
of
the
major rou
123
program
selections which
items. The items
are
to input information
'action'
classify
further
or not
as
grouped as
to
items
rather
whether
the
than
user
is
submenu
required
126
APPENDIX E
E.l
The
119
ASYST Software Usage
software package used
for this
work
is
ASYST,
called
(Keithley-
A Scientific Solution
ASYST
Inc., Rochester, New York) and operates on an IBM-compatible personal com
(PC) directly from the DOS command line. To invoke some command or implement
function in ASYST, a word is activated simply by
entering the name of the word at
puter
some
the ASYST
those
are
those
words produced
System
words
System base
and
line. There
command
fall
words
are always
by
the
under
two
system words
software package and user-defined words are
categories:
words
for
available1
in ASYST:
of words used
user or programmer.
those
are
two type
are
the ASYST
words supplied with
that
To
use.
base
system
are
words and system
supplied
the
with
the versatility
enhance
core
overlay
ASYST
words.
software
the ASYST software,
of
its developers included specialty system overlay words in separate system overlay files
which can be called up and loaded
during processing, when the words they contain are
Since only one overlay file can be loaded at any one time, several system overlay
files (thus all their words) are able to be loaded into and stored permanently to a basesystem program. This base-system program would then be invoked
directly from the DOS
needed.
command
line
immediately
and all
available
The developers
dures
the words, built-in
for
use at
to
or user-defined words
user-defined words
stored
nently
the DOS
in
just
an
command
the ASYST
the ASYST
of
those from the
command
software also
system
overlays,
in that they
system words
application-specific
base-system
line). This
structure employed
was
the
would
be
line.
to
allowed users
their
write
program
be
can
own proce
ASYST treats
perform complex or repetitive processing.
it does
as
and
created and perma
(also invoked directly from
for the first
original program
format described in Section E.2.1.
The developers
own application
files,
along
either
only
the ASYST
overlay files that
the
with
system
one application
simultaneously.
be loaded
of
However,
permanently.
files,
overlay
words
defined
words
program
to be
resident
the
system
concept
in the
employed
be
to
users
user-defined words.
to the
their
create
These overlay
constraint
of
using
time, but never both
overlay
overlay files, application overlay files can not
one at a
is incorporated
by
'permanent'
user-defined words
an overall program
application
for the final
allowed
subject
application-specific
to be included in the
format
their
would
or one system
described in the preceding paragraph.
Efficient use of application overlays in
defined
furthermore
would contain
overlay
unlike
This
software
design
base-system
overlay files. This
and current versions of
requires some
the
and all
was
the
the heart
other
user-
user-
approach and
rate
variability
analysis application software.
The Stack.
concept
1
of a
stack
ASYST actually
but is
not used
The ASYST
is
similar
allows
for this
the
work.
to
software uses stacks
to that
removal of
of a
many
plates
words
store
data
dispenser in
by
during
a
a process called
processing.
restaurant.
Data
The
are
Symbol Table Compaction
APPENDIX E
'pushed'
down
120
onto
the
top
of
the
'popped'
to data processing
stack prior
during
ofF
and
or after processing.
Errors that
during processing may leave items (numbers or arrays) on the
lead
to further errors in subsequent
may
processing if the stacks are not
'cleared'.
ASYST
includes
options
for
users
to program error-trapping and
properly
occur
stacks2
which
routines
error-handling
to smoothly
from
recover
that may
errors
occur
during
the
exe
cution of a procedure.
E.2
The Program Format
Note: The
following
runs
actually
There
the
were
the
and
the
interface,
user
format, the way the
by which the operator
program
method
program.
three
software program
section
discussions differentiate between the
internally,
program operates
major
essentials
of
the heart
rate
the developmental
during
created
describes the
versions
of
the
program
analysis
variability
stages of
this
application
The
work.
formats employed, those
previous
being,
user-
defined words, the application-specific base-system, and application overlay files.
All three versions of the program employed discrete procedures to accomplish specific
tasks.
Because
of
the
highly
variable
nature of
the
data from individual
physiological
patients, frequent operator interaction was necessary throughout the implementation
the program. The primary reason for this interaction was necessary visual inspection
the
a
physiological
procedure
implementation
and was retained
E.2.1
The
data to properly
processing type
start-to-finish
select
parameters
was
program
approach was adopted
in the final
format
user-defined procedures
sufficient
for
feasible
Thus,
A discrete
undertaking.
the initial
during
of
development
program
versions.
for the level
into
used
for the first
a single
of program
original
to
procedure
program
some
key-combination
operating the program,
reference
by
ASYST
the
uses
employed
a
of
Coincidently,
stacks,
need
that
to
stage of
analyze
program
a user
program
incorporated
base-system. This
interface
development.
was
always
which mapped
this keystroke map
a number stack
for processing
changes
used.
available
for the processing of logical values and character strings.
3The rabbits had very high heart rates and therefore the number
subjects.
greater than originally anticipated for human
the
However,
rabbits3, necessary
format
all
approach was
every
the PC keyboard (i.e. <Ctrl-Fl>).
keystroke map
operator.
two types
on
the
specific
during
complexity
version
version of
application-
due to memory constraints resulting from the
in memory usage resulted in a change in the
2
a
processing.
The Original Program Format
original program
The
not
subsequent
of
To
for immediate
was
also
numbers and
major
assist
invoked from
arrays,
in
recall and
a
and a symbol
stack
of
R-wave
peaks
found
was much
APPENDIX E
12i
keyboard key-combination. This original
at the ASYST command line level.
At this stage,
that
errors
during
occurred
procedure and return program control
the
line
command
'stacks'
the
features
more
throughout
E.2. 2
The
ing
and
second
type
task words,
third/final
format
employed used
used
changed.
The
for the first
The final
of
this
utilized
was a great
curve
a
which menu
Any
processed would
few
be
many
contain
user-defined
the
was used with
memory
second
vastly im
usage was
analyzed without
difficulty. The
the keyboard key-combination
to
minor changes
second
The
items
user
inter
to improve
some procedures
final
and
versions
operation of
concerned
interface for the final
user
were selected and
unhandled errors
the
then
application.
the type
version
Recollection
of
used a
This
activated.
a
avoided.
be lost
since
principle operators of
An
additional
of
For example, if Stage 6
primitives
number
menu
the
running
of program
stack
Data loss resulting from
knowledge
a procedure
menu
of which
requires
because
under an
returning
program
interruption
created
in the first two
as
many
versions
and
during menu usage
Subsequently, the data being
runtime errors
primitives4.
and use of
it,
version
running
these
primitives would not
be known
software.
error-handling included involves the processing
(words)
available
the
line. This type
cluttered
using programming
the
level
further for this final
occurring in
procedure and
command
reconstructed
only
with
files,
which
difficulties than just
primitives are
format
overlay
Thus to the operator, nothing had really
used essentially the same program format as
routines were enhanced even
to the ASYST
^Program
base-6ystem,
rates could
program
program.
terminate the
therefore had to be
by
and used
keyboard key-combinations became unnecessary and
by
for new personnel to operate the software was significantly lessened.
active menu would
only be
the
improvement to
The error-handling
the menu interface.
could
for the
invoked
procedures were
more
to incorporate
program.
but included
through
interface
learning
the
version of
difference between the
major
system
control
very little
this,
and speed.
efficiency
interface
application
format,
second program
very fast heart
version of
menuing
of
of
major program versions.
second version used
program
many
program
second program version also entertained use of
the
Because
program grew
developed, improved,
routines were
permanently into it. This
proved and subjects with
user
As the
and an application-specific
With the introduction
the
re-started.
procedures.
of program
procedures stored
face
terminate that
line. Error recovery at
major loss of data since
The Final Program Format
specific
and
be
procedures.
operated
actually
command
correctable without
versatility, error-handling
the
all of
program was
a specific procedure would
procedure
included into the
was
error-trapping
the
cleared and
the
to the ASYST
immediately
was often
be
could
version of
data derived from Stage 5, Stage 6
include basic
outside of
math
operators, array
the menuing environment,
manipulation
at
the ASYST
will
sequence
try
to
procedures,
command
itself.
activate
etc.
line.
These
APPENDIX E
Stage 5 to
processing
so
the data it
obtain
approach
far because
must
is
122
of
manually
the
describing
(should)
to operate,
to
result
E.2.1,
the
program
system and numerous application
source code
the
create
files that
in the loss
names,
format
creation of
and
the
representative source
broken,
is
the
error message
Either way,
not.
total
are a
the
Five
13
other
are
the
of
18
of
of
separate program
these files
are used
descriptions,
support
cally for
a major
cial
same
group
is termed
veloped
file
fall
are
under
and
two
(2)
utility
use
they
only ASYST
These utility
support
support routines
major procedure
that
(1)
that
routines are
system words.
developed
routines
One
of
routine
in the
specifi
to many
are common
in
procedures are
'common'
SERVice Routine (LIBSERVR). Most
used
designed
routines
frequently
The
support.
procedure
major procedures employed
procedures.
categories:
The specifically designed
the
LIBrary
of
and
form
the
found
a spe
from this group
are de
these LIBSERVRs
Other LIBSERVRs, those only used for one procedure
included in the file where that particular procedure is developed.
in the file
for example,
by
as
of routines
a
several smaller
procedure;
major procedures.
in the
by
routines which
to
files
source code
overlay
final program, listed in order of normal use, are shown in Table E-l.
As with any other well structured program, many of the major procedures
program are supported
operator
consists of an application-specific base-
filenames,
code
only be taken
Layout
and
overlay files. Brief
actual application
is
data.
of
application program.
application-specific system-base and
in the
routines can
'chain'
and sometimes one
overlay files. There
up the total
make
chain-reaction
from the Main Menu. An
procedures
the problem,
occur
This
and so on.
'prior'
When this
Program Source Code Development
As described in Section
used
able
employed.
the necessary
activate
no runtime errors will
E.2. 3
format
program
displayed
sometimes
in
needs
to automatically invoke
necessary
thetllc.prg.
The
general appearance and contents of each program source code
the
main
program
file (thetlOa.prg).
For readability,
each
file is
file is
represented
in
arranged
a
beginning which describes the file contents,
developed within, as well as declarations
necessary existing words, procedures (words)
The procedure description header, at the beginning of every
of locally used variables.
procedure in a file, contains a brief procedure description, as well as a list of the routines
specific manner with a
which
own
it calls,
following
This
heart
those
category in the
procedure
E.3
and
large
at
section
routines which
procedure
description header.
call
it. LIBSERVRs
description header.
The
called are
Figure E-l
name
procedure
always
shows
listed
an
under
their
example of a
follows the header
on
the
line.
The Menu-Interface
section
rate
the
describes in detail the
variability
screen output are
of
operation
analysis process.
included to
assist
the Application Program
Many
of
the
application
examples of
a new user
in
software
the displayed
becoming
familiar
for
a normal
menus and normal
with
the
program.
APPENDIX E
Table E-l:
in the
123
Listing
descriptions,
of
names and source
PROCEDURE
DESCRIPTION
Data
seconds of collected
Convert to
Plot 20
Set
the
major routines
NAME
FILE
Analyze. EKG
Recall. Data
thetl 3a. prg
Compute. IHR
thetl4a.prg
thetl4a.prg
Plot.EKG
Set.Parms
search parameters
dataset
processed
thet2#a.prg
thetl7a.prg
thetl2a.prg
thetl7a.prg
thtl9a.prg
thetl2a.prg
Plot. Channels
Convert. File
real values
seconds of real values
Retrieve
SOURCE
data
Peak detection
Compute instantaneous heart
Plot instantaneous heart
rate
Plot.lHR.T
rate
Patch instantaneous heart
rate
Patch. IHR
Parse instantaneous heart
rate
IHR. Parse
Compute heart
Plot heart
Smooth heart
Compute
Plot
Set
rate
rate
Window heart
rate
density
density
bandwidths
powers/ratios report
processed
dataset
activates
\
filename is
\
a
"NULL,
\
<D
general-use
\
*/.
'/. LIBSERVR:
and
left
the
Smooth. HRV
variability
Store
routine
Window.HRV
power spectral
frequency
for validity
Plot. HRV
variability
Print
the
filename
type based
in the
routine
Error
was
.Scrn.
thetl4a.prg
thetl4a.prg
thetlBa.prg
thetlBa.prg
thetlBa.prg
thetlBa.prg
Compute. HRV
variability
variability
rate
power spectral
\
\
of
PROCEDURE
Get. Data
collection
Plot 20
\
\ This
file locations
program.
on
Compute. PSD
thetl
a.prg
Plot.PSD
thetl
a.prg
Set.PSD. Bands
thetl 9a. prg
Smooth. HRV
thetl8a.prg
Store. Data
thetl 3a. prg
prompt
the
current
str-var:
window
opcode
.file$
terminated, usually
On, Error
.Scrn.
and
passed
on
tests
the
entered
N.stk.
for testing.
with
the
<ESC>
filenames
The
If
entered
it
contains
key.
Off
\
Filename. Prompt2
Figure E-l: An
@
sign
those
\ [
file. type
example of a
lists those
routines
routines which
this
-]
(
routine.
title
cur.
filename
Procedure Description Header. The line
that
call
this
routine calls.
one.
The
line(s) beginning
LIBSERVRs
called are
beginning
with
listed
-)
the
%
with
sign
separately.
the
lists
APPENDIX E
Just like many
of submenus.
layered
124
other programs which utilize
For
quick
The
program
is
in Figure E-2.
stages
used
(Figure
during
E-2)
The item
the
listing
end of
of all
this
the
the Main Menu
use
and
appendix.
of
heart
two areas, the
rate variability.
item selection
specific procedures.
to
The processing
which procedures
have been
for regulating the
area,
The
display
and
the processing
items for
menu
screen
Data Acquisition
status area.
important
action of certain procedures.
STATUS LIST
cur
STORE Data to File
.
ekg
graph
peaks
ihr
FUL
NO
NO
EKG:
Plot
SET:
Search/Program Parms
ihr. patch
NO
EKG:
Analyze/Find-Peaks
SET:
PSD Ranges/Labels
hrv
NO
smooth
NO
IHR:
Plot
IHR:
Patch/Plot
PLOT AREA:
IHR:
Parse
PLOT AREA:
(time)
HRV:
Plot
PSD:
Plot/smth (auto-fit)
PSD:
Plot/smth
(normal)
(user-fit)
Top
window
NO
psd
NO
Create Multigraph
psd. power
NO
Full Channel
respira.
NO
Bottom
Display
Process Respiration Data
REPORT:
Print Cover Page Data
REPORT:
Print Band Data/Ratios
RESHAPE Acquis.
REPORT:
List Band Data/Ratios
MANUAL
:
File
freq
freq
plot
Single Commands
cutoff
EXIT to ASYST
Figure E-2: The Main Menu
the Menus.
the <Home>
return
key
from that
or
<End>
of
the
volt
.95
min.
time
256
256
to its
a selection
parent menu
from
a menu
is usually
zoom.w
95
ihr V.
20.
#psdbands
5
#psdratio
4
application program.
Selecting a menu item requires using the
keys) to highlight the desired menu item
(<RETURN>). If
submenu
display
1.0
5.0
min.
scan.w
EXIT to DOS
to
information
performed as well as current values of
Transfer Single Channel
Using
is
the Main Menu
status area maintains up-to-date
RECALL Data from file
File Editor/DOS Utilities
of
selection of submenus or
Pediatric Head Trauma Analysis Application
GET:
with
processing
an analysis
consists of
parameters used
at
is layered
from the Main Menu and its appearance on the
The Main Menu provides direct access to all major
selection area provides access
concerning
index
an
items is included
program
operated
shown
invoke
reference, there is
submenu selection
menus, the
launches
accomplished
cursor
and
a
by
keys
(including
then pressing the
submenu, returning
pressing the escape
APPENDIX E
125
key (<ESC>).
be
to
selected
Most
return
the
of
to its
Program Start-up.
the program
at
the DOS
being
after
>
by
'Y'
response of
to the DOS
command
terminating
the
invoke
a
it is invoked
and
Selection
'y',
or
No
program.
can
with a single parameter called
the EXIT to DOS item
operator
is
All
menu selections
(2)
those items
for data
responsible
fall
under
two
directly
which
the Main
on
program and return
automatic storage of processed
and
submenu,
of
terminate the
will
line. Note: The
Menu Item Types.
which
item that
EKGASYST NOP).
Program Termination.
followed
program possess a menu
The Main Menu is the entry point (and normal exit
point) of
invoked from the DOS command line. The program name used
line is EKGASYST
command
NOP (e.g. C:\
in this
menus used
parent menu5.
Menu,
control
storage prior
data is
categories:
initiate
PC
to
performed.
(1)
those items
some procedure or
action.
There
are
five Main Menu
selections
e
File Editor/Utilities
e
SET: Search/Program Parms
e
SET: PSD Ranges/Labels
e
Create Multigraph
e
MANUAL: Single Commands [R].
that invoke
a submenu which are:
[L]6;
[R];
[R];
[R];
and,
All remaining 22 Main Menu selections invoke some
action selections are listed in Table E-2.
There are ten
perform
type
some
action
of operator
without
input,
There
the
menus such
that
Prompt Window
and
and
twelve
selections
selections
or
'action'.
immediately
which
which
do
These
require
some
filename.
a
usually
Special Windows.
input
user
procedure
that
frequently used throughout
they require their own introduction. They are known as the Filename
the Routine Processor Window, and are shown in Figures E-3 and E-4,
are
two
windows
are so
respectively.
The Filename Prompt Window
input
of a
is displayed
5If a
is
filename is
necessary.
This
prominently.
submenu possesses an
always an option
6The location
of
Exit
but
will not
the
menu
be
(FPW)
As
routine
...
menu
is
is
for
supported
item,
use of
mentioned again
item is indicated
used
most all
in Figure
seen
by
E-3,
instances
LIBSERVRs
the <ESC>
where operator
the type of file to be
key
to
which check
return
to its
used
for file
parent menu
in this discussion.
within
the
brackets, [L] for left
side or
[R]
for
right side.
APPENDIX E
Table E-2:
126
Main Menu
items. The items
are
selections which
further
classify
grouped as
to
as
'action'
whether
the
items
user
is
rather
required
than
submenu
to input infor
mation or not.
Action
IHR: Plot
(time)
Only (10)
Requires User Input
[L]+
IHR: Patch/Plot
Transfer Single
HRV: Plot
IHR: Parse
PSD:
EKG: Plot
[L]
(normal) [L]
Plot/smth (auto-fit) [L]
REPORT: Print Cover Page Data [L]
REPORT: Print Band Data/Ratios [L]
REPORT: List Band Data/Ratios [L]
PLOT AREA:
Top [R]
PLOT AREA: Bottom
EXIT to ASYST
+The item in
the
[R]
[R]
menu
(12)
[L]
Channel [L]
GET: Data Acquisition
listing
is
on
the
[L]
[L]
EKG: Analyze/Find-Peaks
[L]
(user-fit) [L]
EXIT to DOS [L]
RECALL Data from File [R]
STORE Data to File [R]
Full Channel Display [R]
Process Respiration Data [R]
RESHAPE Acquis. File [R]
left [L] or right [R] side.
PSD: Plot/smth
Data Channel Transfer Routine
Source File Type:
ORIGINAL INTEGER
<ESC>
to EXIT
<RETURN>
Current filename designation:
Enter filename
or
keystroke:
test80.dat
Figure E-3: The Filename. Prompt Window
name of
the
particular
routine
for Current File
NONE/SET
using the
display
window
case, the Main Menu selection, Transfer Single
for entry of filenames. Note the
is displayed in the title bar. In this
used
Channel,
is in
use.
127
APPENDIX E
ROUTINE PROCESSOR WINDOW
(ZERO
SELECT ONE TRACE to TRANSFER:
Select
)
2
) RES
3
) PI
4
) P2
) P3
5
Figure E-4: The Routine Processor Window has
The
a vertical space of
running is Transfer Single
particular routine shown
Channel,
qUIT)
1
channel:
a
to
EKG
12 lines to
display
text.
from the Main
selected
Menu.
existence,
file type,
generates
this
and other
things
window accepts a
which
may
cause a runtime error.
default filename
is
which
The
routine which
the
major routine
by
supplied
'knows'
invoking it,
type
of
this
makes normal
datafile it
As
needs.
processing faster
the top-right
at
shown
since each major procedure
of
the
'fits'
able
The FPW
pressing the <ESC> key.
the
is located near the top of
display screen.
to be terminated
the Main Menu
and
by
The Routine Processor Window
query
to
the bottom
near
E.4
Using
This
section
they
would
of
the
describes the
be invoked
use and
during
action
taken is the
It
directly
heart
of
'Selection
of subfile number
known target disk drives
is
explained
are checked
for
is
an action
56 for the
available
for
another
item
of
comments
(64
characters
which
the Main Menu but is
which
under
the
amount of
number
of acquisition
space).
created and
queried
allocated, otherwise, the
procedure
is
offered
the opportunity to enter,
to the
each) relating
experiment
or
patient.
and/or
The
asks
..
.
operator
as
the Main Menu. The
lost disk
filename.
After file allocation, the
display
for. At this point, the
tabs being in place. If sufficient
space, and write-only
is
for a filename. A check for duplicate filenames
queries
is available, the FPW appears
file is
target
the
performed and, if there are none,
space
must
12 lines in
item in the Main Menu
in Section 2.4.1 desired is
and
that
rate analysis procedure.
the RPW in
on page
and number of
of
beneath the FPW.
subfiles7
channels
of
is
the borders
Normal HRV Analysis
a
selection
appearance
possesses
the borders
effects of each selection
a normal
This
screen.
major routine
within
most all procedures
within
screen,
the Program for
GET: Datn Acquisition.
first
also
display
for
display
'fits'
this task. The RPW
located
used
information to the
prompts or status
accomplish
is
(RPW)
the
display,
what
change,
number
seven
of
lines
channels,
APPENDIX E
128
The data is originally collected to the hard drive but
is transferred to a Bernoulli
the data collection process. This file is
the integer data file mentioned in
Section 2.4.1. The procedure is completed at this point
cartridge after
and program control automati
cally
returns
to the Main
Menu.
DOS Utilities t Comment Editor Menu
Plot All Channels
20
-
sec.
Edit File Comments
Directory
Directory
Directory
Directory
D:
Copy_File
C
Rename_File
B
Delete_File
A
Exit to Main Menu
Figure E-5: The DOS Utilities & Comment Editor Menu
commands, data file
file.
comment
File Editor/DOS Utilities.
At this
shows
point
the resulting
the last
Selecting
filename,
data
and
date
collection.
can
display.
menu
Finally,
the
this
end
of
menu
and
The
subfile collection
cedure at
the
data
original
This
and
selection
be
viewed
Only
item (Exit
time
of
approximate
for
duration
as
pressed
of
the
a submenu
access
item
under
anomalous points or
will
are
the
begin data
during
to the disposition
into
acquisition process
20
data in
a
data
the Main Menu.
trends. Figure E-5
column of
this
menu
to the Main Menu.
an eighth comment
line just before
is displayed in the RPW. A
nominal
seconds.
collection or
<ESC> to terminate the pro
the data collection, the
of
DOS
various
be described later in Section E.5. 2.
'stamped'
minutes and
to
collected
will return program control
<RETURN>to
If <ESC> is
the acquisition)
of
allows
the first two items in the left
experiment
lasts approximately 4
operator presses
point.
the
...)
viewing
is
described here. The DOS functions listed
are
256
the
line editing,
the file just
created
operator will
and
filled.
be
queried
(at
DO NOT USE
THE <CTRL-BREAK> KEY COMBINATION TO TERMINATE THE ACQUISITION
PROCESS. If <Ctrl-Break> is used, the PC must be re-booted, all data will be lost, and the DOS
'lost'
CHKDSK program will have to be used to reclaim the
allocated file space (see Table 5
APPENDIX E
12g
Plot All Channels
20 sec. This selection is an action item under the
File Editor/DOS Utilities Menu. The datafile to be viewed is
selected through
use of the FPW. After
a graphical
entry of the
of
-
filename,
one
for
point
each
channel,
(msec.) in the first 20
to
dump this graphical display to
key. Pressing the
key erases
'Q'
menu
to its
the
seconds of
display
displayed8
The data
will appear.
collected
the printer, if
the
graphical
strip plots,
represents
every
data. There is
eighth
an option
'P'
desired, by pressing the
display and will return the
previous appearance.
File Editor/DOS Utilities Menu
File:
1
)
Joe Patient
2 )
3
80
second
for EKG
record
and
respiration
)
4
)
5
)
6
)
7
)
)
8
TEST80.DAT
a
volunteer
#Chnls:
2
lab
File:
subject
TEST80.DAT
Edit File Comments
Date:
Modify
07/19/91
Time:
05:34
Status-Comment-#8
File Comments
Display
Display
Subfiles Contained Therein
Exit from Menu
Figure E-6: The File Editor/DOS Utilities Menu
contents of a
allows examination of
data file. Comments lines in the datafile
Edit. File Comments. This
selection
is
can
be
the
comments and
edited as necessary.
a submenu
item
under
the File
The resulting submenu, which contains a 'win
the display, is shown in Figure E-6. Selecting the last
Editor/DOS Utilities Menu.
dow'
near
menu
the
top
item (Exit
of
...)
will return program control
to the
previous menu
(File
Editor/DOS Utilities).
Display File
under
8See
of
This
the Edit File Comments Menu.
the description
displaying
Comments.
collected
of
the Full Channel
data.
Display
selection
The
selection
is
window
an
action
just
item
mentioned
from the Main Menu for
an alternative means
APPENDIX E
130
contains
a
listing
is displayed
ments window
Display
item
tioned
window
stored
replaced
datafile,
the
this
by
of
an alternate
this
which
value of zero
comment
(0)
restored
will
the file
and
the
Selecting
previous
contents
edited.
some position
complete, the
comment.
The
<RETURN>
normally,
to its
contents of
listed.
the
in
the
a prompt
Entering
a
parent menu
Upon entering a valid
the current comment displayed
appearance of
with
a
editing
key
the file
'residue'
prompt
in Figure E-8.
cursor
Moving
key.
The
the
pressing
state of
When editing is
be pressed to update
action.
indicated)
comments
previous appearance.
the
comment requires
must
<ESC>(as
update
]
displays the
edited.
action and
in the existing
Pressing
2
appearance.
key simultaneously
<Insert> key will affect the
menu
of
selected.
will result
(line number) is to be
the <Ctrl>
the
type
a submenu selection under
subsequent submenu are shown
procedure
item is
selection
this item
a submenu will appear with
is ready to be
the
lines. This file
comments are
terminate further
to its
and
the
and
1
Edit File Comments. This is
cursor
in
information relating to
menu
Contained Within
Edit File Comments Menu.
to
shown
window,
INTEGER DIM[ 1024
type
same window area where
number,
com
selected.
namely, the number, size,
when
subfile:
Display Subfiles
be
item is
TEST80.DAT
subfiles
Current
will
This file
comments
80
asking
menu
number of comment
is displayed
File:
Figure E-7: The
when
alternate window contains
in the
window
8
be
can
subfiles as well as
listing
originally
into the datafile
recorded.
under
Figure E-7. This
is
comments placed
was
Subfiles Contained Therein. This selection is an
the Edit File Comments Menu. The above men
action
data file in the
eight
the physiological data
when
what
the
of
will
terminate the
window,
and restore
the
APPENDIX E
131
Enter Comment Line Number to
<ESC>
to
complete
Comment:
a
comment
lab
volunteer
Figure E-8: The Edit File Comments
then
allows
editing to proceed. The
This
is
used
To enter/modify
to
alter
#8. This
the
information,
is
example shown
the
move
is
previous
a submenu
is
submenu
shown
item
figure.
under
comment
to highlight the
corrections and press
to edit,
in Figure E-9.
'time-stamp'
the
cursor
to the
relates
selection
contents of
<RETURN>. Make the
and press
quit
to
to EDIT
subject
Comments Menu. The resulting
submenu
(zero)
0
<CTRL-cursor>
menu selection queries a comment number
Modify Status-Comment
the Edit File
4
edit :
line.
line
specific
<RETURN>
again.
When complete, pressing <ESC> will update the file comments window and
the parent menu will then be restored to its previous appearance.
Note: this procedure was developed to assist in
old-version
updating
datafiles to the
original
format
current
datafile format did
number of actual physiological signals
the
acquisition algorithm allowed
data
which physiological
#Chnls:
File:
#
#
Originally
Recording
status
Recording
line in
a
Recall that data is
integer
numeric
channel,
convert
As indicated
<ESC>
the
by
format. This
present
real
work, this
The datafile to be
Time
only
processed
and
is
the
is
hh:mm
2
07/19/91
(24Hr)
is
used
then
RPW,
an
to
write
the
05:34
menu
allows
action
item
be
used
selected
this
adjustment
under
of
the
converted
of
this list
appears
constructs
data into
be interrupted
a new
by
in
an
a single
datafile.
pressing the
data is necessary in
the channels in the datafile.
channel
through the FPW. A list
to be
the Main Menu.
the data representing
the EKG
for any
specific channel
appearance of
extract
process can
conversion of
procedure can
is displayed in the RPW
list. Coincidently, the
and
in the
although
versions of
Time:
xx/xx/xx
Date
selection
procedure
voltages,
a message
key. Note:
Date:
into the integer datafile in two-dimensional
collected
it to
Later
number of channels
data files.
This
Transfer Single Channel.
originally
Sample Below
Modify Status-Comment-#8
The
The
channels regardless of
only that
Recorded Channels
'time-stamped'
five
were present.
of
recording
filename.DAT
Original
E-9:
that
needed.
of channels
was supplied.
Original
Figure
number
Status-Comment-#8
Modify
infrequently
were always recorded
the
for
is thus
and
include the
not
Original datafiles
recorded.
used
'transferred'
of available channels
is
selected
in Figure E-4. After
from this
a selection
is
APPENDIX E
a
made,
132
processing
the total
The
file,
output
(i.e.
channel selected
EKG: Plot.
This
to graphically
single-
display
filename9
original
Although the
is
item
an action
by
Analyze/Find-Peaks.
The RPW
appears
processed out of
RPW,
the
name
This
(EKG:
seconds
through
selected
use of
and
process
Plot)
is
selection
maintains
the total
is
deceiving,
of a
this
on
indicating
the FPW
file
the
the
under
in the
and
the
graphics
be
the Main Menu.
which subfile
is
used
procedure.
use of
by
Thus
the FPW.
is currently
in the datafile. As indicated
by
(subfiles)
procedure can
file through the
real voltage
a counter
be interrupted
item
an action
number of subfiles
can
new
procedure
and use of
described Transfer Single Channel
above
for the filename
procedure prompts
a
based
the Main Menu. This
under
in the the first 20
eighth point
file. The filename is
the
assigned
.PI).
every
item
menu
created
processed out of
a new extension
and
image is automatically displayed. Discussion
menus is deferred until Section E.5.1 (page 135).
for any datafile
being
is automatically
file,
voltage
graphics
environment
the
or
selection
channel real voltage
resulting
real
using the
.EKG
is currently
which subfile
in the datafile.
termed the
(filename)
specification
used
line indicates
status
number of subfiles
being
a message
pressing the <ESC> key. Upon
in
procedure
display is automatically restored. At this point, the STATUS
Window indicates EKG peak detection is completed by changing the ekg peaks status
completion, the Main Menu
'NO'
from
to 'YES'.
IHR: Plot (time).
tion
combines
neous
heart
two distinct
rate
(IHR)
is
procedures
activated
the ihr
status
is
checked prior
IHR: Patch/Plot.
This
lection
two distinct
also
2.4.2)
combines
Since the IHR.Patch
dataset (R-R intervals), the total
status
ing
into
one.
item
The
under
the Main Menu. This
to
procedure
immediately by
status
is
peaks status
the
is
compute
selec
the instanta
to graphically
procedure
modified accordingly.
checked prior
As
to computing the IHR
to plotting the IHR dataset.
selection
the instantaneous heart
procedure.
Upon
an action
followed
to in Section E.2. 2, the ekg
referred
tion
is
selection
the resulting dataset (Plot. IHR. T). The ihr
display
and
This
is
an
procedures
rate
is
item
action
into
activated
procedure
one.
The
followed
involves
number of points
the Main Menu.
under
procedure
to Patch
immediately by
removal
removed
of points
This
se
(Sec
the Plot. IHR. T
from the IHR
is displayed in the RPW.
termination, the Main Menu display is restored. The ihr. patch
accordingly.
As above, ekg peaks status is checked prior to patch
normal procedure
is
and
modified
re-
computation
of
the IHR
and
the ihr
status
is
checked prior
to the plotting
procedure.
9Speaking
filename
and
DOS concerning file specifications, in
'typ'
portion is the extension.
the
a
file
named
'myfile.typ',
the
'myfile'
portion
is the
APPENDIX E
133
IHR: Parse.
was not
This
is
selection
an
described in Section 2.4.2
may be
The Parse
routine
before
used
under
allows graphical
it to
inspection
replace
the Main Menu.
the processing methodology
when
or after application of
routine10
of a contiguous portion of
item
action
of
the
Patching
key,
which
the
controls
mention made
'step-size'
taken
here
when
a
concerns
are
covered.
and possible extraction
useful
included
the function
is
key
cursor
just
in
removal
removal of glitches
Parsing
described. The only
selection
detailed. This
procedure
the IHR dataset
linear trend existing in a portion of the IHR dataset or
'end'
are near either
of the IHR dataset.
The instructions for operation of the
environment
so are not
was
the existing IHR dataset. This is
of a
This
pressed.
if they
on-screen and
of
the <PgUp>
After pressing
be one dataset-
<PgUp>, if the next key pressed is a cursor key, then each 'step' will
point in size. To increase the number of points in a 'step' to
say 10 dataset-points,
<PgUp>
followed
by
the
'1'
'0'
and
keys
the
at
top
of
the
keyboard,
then
press
press a cursor
key.
When completed, the routine re-computes the IHR dataset
IHR dataset concurrently in a split graphics window. The ihr
if it had
been
not
re-computation of
HRV: Plot (normal).
selection combines
rate
variability
display
This
(HRV)
the resulting
is
and progress of
accordingly.
selection
an action
into
procedures
followed
item
The
one.
under
is
set
to
the Main Menu.
procedure
immediately by
dataset (Plot. HRV). Since this
stage
the
to
compute
a procedure
This
the heart
to graphically
involves the interpolation from
status
an
is
checked prior
to computing the HRV
and
the hrv
status
to plotting the HRV dataset.
PSD: Plot/smth (auto-fit).
This
status
new
'YES'
R-R interval function (Section 2.1), the RPW appears
the interpolation is indicated by a message. The hrv status is modified
The ihr
checked prior
is
selection
activated
R-R interval dataset to
an
is
and
two distinct
displays the
The ekg peaks status is checked prior to parsing and
the ihr status is checked prior to the plotting procedure.
previously.
the IHR
and
combines
This
several
selection
distinct
is
an action
procedures
into
item
one.
under
The
the Main Menu.
procedures
included
are:
1.
Apply
a
Hanning
window
2. Blackman filter this
new
to the HRV
dataset
at
3. Compute the fast Fourier transform
4. Calculate the
power spectral
5. Calculate the PSD
10
In ASYST, this
dataset;
five
of
hertz;
this
dataset;
density (PSD);
powers and ratios as
routine uses a restricted
form
of
defined
by
the
current
the GRAPHICS. READOUT
parameters; and,
system word.
APPENDIX E
134
6. Plot the resulting PSD dataset out to a
frequency set by the
(indicated in the STATUS window on the Main Menu display).
freq
plot
value
The smooth, window, psd, and psd. power status indicators are modified accord
ingly. The hrv status is checked prior to application of Blackman filter, the Hanning
window,
and
the PSD
The
calculation.
is
psd status
to plotting the HRV
checked prior
dataset.
PSD: Plot/smth (user-fit).
This
selection performs
Menu item
erator
is
exactly the
with one exception.
prompted
useful when
for the
producing
This
is
selection
same
an action
functions
graphs which are used
the Main Menu.
under
the PSD: Plot/smth
as
the plotting
During
of
to be
maximum y-axis value
item
the resulting PSD
dataset,
the op
This feature is extremely
plotted.
to visually
Main
(auto-fit)
compare relative spectral power
amplitudes.
Process Respiration Data.
This
procedure
window
second
This data
window
processed
from the
is then
this
above)
extracted
the
original
dataset
from the
datafile,
REPORT: Print Cover Page Data.
Menu. This
the
about
This
procedure produces and sends
analysis process.
cessing parameters,
and
The
dataset
comments
selection
to the
in the
status
is
the bounds
and must
be
of a
entered.
is
(same
set accordingly.
Since
datafile,
be
need
an action
printer a report
item
in the
characteristics are reproduced
checked.
under
the Main
containing information
important
all
of
obtained
indicators
no status
and
dataset is
density
respira.
the integer data file
of
for
the Main Menu.
dataset for determination
respiration
The
under
appears
are prompted
power spectral
graphically.
integer
item
for the filename
FPW)
respiration
displayed
and
routine uses
an action
EKG data. The RPW
the dominant respiratory frequency. A
steps as
is
selection
(through the
prompts
corresponding to the just
64
This
search and pro
report made
by
this
Additional information concerning the specified frequency bands is produced
includes various items such as: total band power, band power ratios, band peak
procedure.
and
amplitude ratios
in Appendix D
and others as
which contains
described here. This
This
tent
E.5
The
of
concludes
the heart
well.
the
procedure checks
the
rate
the default
operating
example of
program output
the
variability
the
form
report
from the
produced
normal analysis
psd. powers status
normal steps of analysis
necessary to
during
obtain
is
shown
procedure
its
operation.
the
frequency
con
of some studied subject.
Additional Features
general
An
procedures
of
the Program
described
above are sufficient
program parameters without graphical output
in
for
an analysis
hardcopy
using
form. There
all
are
APPENDIX E
the default
ing
features incorporated into the
additional
many
graphical
E.5.1
In
135
program
and
plots,
the graphical
inferred that
the
occupy the
are
half
data,
top half of
processed
area
an operator
storage and retrieval of processed
DOS file
simple
is the full
output generated
additional
here they are.
First of all, there
so
implementing
assist
data,
in
alter
combining
management commands.
Graphics Environment Menus
describing
was
parameters,
to
program
two types
the
were available while
of plot areas
screen and
full
that
can
screen areas.
display (TOP)
screen area
the desired plotting
features
for the EKG: Plot Main Menu selection, it
in the
be
for
used
The half
graphics
environment,
display
graphical
screen plot
areas
of
simply
the bottom half (BOT). The default plotting
or
(FUL). The default
to
plot area can
be
superceded
by
selecting
This
selection can
invoking
be done directly from the Main Menu by selecting one of the the two PLOT AREA: menu
items. The first item in the STATUS list, cur. graph, indicates what the current plot area
is. Upon
is
set
its default
All
of
analysis
menu
return
located
environment
previous
the
procedure.
to the Main Menu from any Main Menu selection, the
value
plot
at
used
the lower left
located in the
are
upper
portion of
of graphics
from
accessible
one
of
the
plot
left
right
area
of
of
the
display screen with
display and an options
the
the display.
available
is
or
in
to
which
create
upon normal
(or the
options
The Multigraph Menu is the
from the Main Menu
80%
portion
environments
The GRAPHING Menu is
sections.
current plot
(FUL).
areas
two type
are
own menu.
directly
the graphing
information displayed in the
There
its
the
area prior
respiration
graphs,
each
entry into the
with
graphics
procedure) described in
environment and it is
second graphical
available as a submenu selection
item from
GRAPHING Menu.
GRAPHING
Put Comment
Print Graph
Multi-Graph
Set Max
<ESC>
Figure E-10: The GRAPHING
hard copy,
frequency
comment
insertion,
plotted can also
be
menu allows
and
Freq
to
Exit
various
options
entry into the Multigraph
changed
for
spectral plots.
for
plotted graphs:
environment.
The
printer
maximum
APPENDIX E
136
GRAPHING Menu.
items
including
EXIT
an
The GRAPHING
Menu,
in Figure
shown
Put Comment. This selection is a submenu item
Menu environment. The appearance of the submenu is
This
submenu allows
the
creation of
two
in Figure E-ll.
(0.0-1.0 )in the
the
the
center of
Erase.Label
Orientation:
values
to ninety (90).
Character: fields to
and
Apply
Label
1
Label
2
Locate X
a
Locate Y
Erase_Label_l
Apply.Label.2
Erase.Label.2
TOP
FULL
two
environment.
portion of
the
This
"Label:
printer
environment.
controls
This
system,
Label:
replaced
direction
entered
is
The
by
selected
0
Character
:
updates
the
is
an
the
prints
selection
is
0
in degrees.
to EXIT
<ESC>
allows creation
Menu,
generation
The
plots
the GRAPHING
current menu
a submenu
any
under
from the lower
information in the
display
to printing to
the Multigraph
generated.
the
the resulting
appearance of
it is
item
action
analysis
verified prior
of comment
FUL
:
from the GRAPHING Menu
procedure removes
This
orientation of each character as
coordinate
can
labels.
selection
display,
display, and
Multi-Graph.
ING Menu is
Menu,
the
the
presence of
Menu
(0).
by setting both the
be formed by setting
Graph Label
Current
separate graph
Print Graph.
portion of
zero
other values11.
BOTTOM
Figure E-ll: The Put Comment
and placement of
left
to
obtained
.9500
Apply.Label.1
Menu
Character:)
and
Unique labels
Orientation:
.5000
current plot area can
by normalized coordinates
improperly can be removed
horizontal orientation are obtained by
setting both of the Orientation: values (Label:
Labels in a vertical orientation (facing
right) are
the Label:
placed
which are placed
Labels in
selections.
may be
the label is defined
Labels
plot area.
which
menu
to the Main Menu.
the GRAPHING
any location in the current plot area. Note that the
also be selected from this submenu.
of
four
under
labels
separate
offers
shown
at
The location
E-10,
option which will return program control
...
under
The
the GRAPHING
unaltered and
which
printer.
left
avoid a runtime error.
item
is
to the
upper
is
shown
from the Locate:
the GRAPH
in Figure E-12.
position.
values represent angular units
Character:
in
controls
a standard polar
APPENDIX E
137
Multigraph
TOP
BOT
IHR.T
HRV
(orig.)
PSD
RESP
IHR. I
HRV
(smth/w)
Vuport
Figure E-12: The MultiGraph
the
menu allows
This
The
the
menu
but
the
menu.
To
graph
placement of
two
active vuport
(plot area) is
always
can
create a
to
plot
be
by
changed
select
multigraph,
(i.e.
in that
PSD)
select another graph
type (i.e.
GRAPHING Menu,
Print Graph
run
vuport.
maximum
E.5. 2
data
on
Apply
at
display
Then
of
the
of
in the
labels,
Comment
the
select
the BOT
select
top
specific
vuport
To
second vuport.
press
con
the bottom
and
obtain
<ESC> to return to
procedure and
then invoke the
is
a submenu
submenu generated
Search/ Program Parms
frequency
to
plot out
selection
submenu at
to
item
when
under
the
GRAPHING
from the Main Menu
and
this
point allows
graphically
when
is detailed in Sec
displaying
changing
the PSD
RESPiration datasets.
little thought,
through the
some
use of
interesting
both graphing
plot combinations and
environments
labelling
can
be
accom
just described.
Supplemental Program Utilities
With the
can
a
indicated
an alternate vuport at
plot
descriptive
tion E.5. 2 (page 139). Access to this
and/or
to
the
plot areas on
say, the TOP vuport, then
selection
The is the identical
selecting the SET:
plished
graphs of processed
procedure.
Set Plot Freq. This
Menu.
the
selecting
RESP)
a printout of a multigraph with
With
two
of
the
environment allows
currently.
the
plotting
display.
same
the
BOT
:
graphics utilities now
commence
by describing
discussed,
coverage of
the
the remaining individual
supplemental program utilities
menu
selections
from the Main
Menu.
File Editor/DOS Utilities.
This
portion of
the
menu
item
This
covers
selection
the DOS
is
a submenu
utilities
that
item
under
were not
the Main Menu.
discussed
previously.
APPENDIX E
138
Referring to Figure E-5 (page 128), these DOS utilities include
DIRectory fist, DELete file, COPY file, and REName file.
D: This
Directory
Utilities Menu. This
directory
filename,
used as
resulting
display
the
is
filename'
can
shown
*
*
.
be
DISK SPACE INFORMATION
*
*
9.06'/.
90 947.
Total
21
,204,992
100.00*/.
:
Move
with
<DIR>
08/02/91
08/02/91
7839
08/02/91
THET14A.PRG
3523
08/02/91
THET15A.PRG
3599
08/02/91
THET16A.PRG
2109
08/02/91
THET17A.PRG
6317
08/02/91
THET18A.PRG
6006
08/02/91
Directory Display
the files
requested
This
This
allows
for the
selection
is
procedure
available
listing by
an action
produces
a
a
space on a
quit
pected
and allows
item
under
small
the File Editor/DOS
window
(not shown)
and
the target filename. The <RETURN>
pressing
<ESC>.
If
from the procedure,
because
of
Utilities Menu. This
used
for file
no
filenames
nature of
selection
procedure
renaming.
are entered and
an error message will
the operating
Rename_File. This
but is
drive
scrolling feature.
for the copy source filename and
The
must be pressed after the entering each filename.
by
<PgDn>
03:13p
03:13p
12:24p
12:37p
12:26p
12:27p
12:27p
12:28p
12:29p
lists the
prompts
voked
ft
<PgUp>
\USERPROG\ASYST\ JUNK4
08/02/91
-File.
The
.
<DIR>
Utilities Menu.
same
*
,283,968
2441
to
(C:)
,921,024
THET13A.PRG
Figure E-13: The
invoke the
search parameter.
1
THET12A.PRG
key
the
19
C
.
Copy
used as
Directory Listing
of
examination of
selections
Used
EXIT
Directory
Directory
in Figure E-13.
Available
to
three
Editor/ DOS
being the default drive specification passed
directory command (DIR), the current
default search parameter. Also, a specific path, specific
'wildcard
*
<ESC>
other
the File
under
commands:
Just like the DOS
routine.
or a
the
and
item
an action
following
the only difference
procedure with
to the FPW
is
selection
the
is
the
an action
functions
procedure
<ESC>
is
is in
pressed
be displayed. This is
ex
procedure.
item
identically
under
as
the File Editor/DOS
the Copy.File
procedure
APPENDIX E
139
Delete_File. This
Utilities Menu. This
the FPW. The
the
and
file
or not.
the
file,
As
found
file(s)
operator
a
is
selection
an action
procedure prompts
by
the delete
is queried, for
feature,
safety
a response of
'Y'
is
for
each
a
item
filename to be deleted through
displayed in the RPW
procedure are
file
the File Editor/DOS
under
found,
as
to
simply pressing <RETURN>
sufficient
will not
delete
required.
REPORT: Print Band Data/Ratios. This selection is an
Main Menu. The first of the REPORT: menu
items, described
gives
to delete the
whether
data concerning the
results
the
of
analysis
item
action
on
page
under
134,
normally
detailed
However,
process.
the
information concerning the frequency bands and other seldom used ratio computations
can be generated. This procedure produces a report form with this additional information
it to the
and sends
to
printer
hardcopy.
produce a
REPORT: Print Band Data/Ratios.
This
Main Menu. This procedure produces exactly the
the REPORT: Print Band Data/Ratios
directs the
STORE Data to File.
of
processing
eliminate
processed
these
The FPW is
already
the data
This
during
data
special storage
to
used
at
a
item
action
form
files,
under
is
an action
item
under
to
the
operator
to
file.
data
This
or
new storage
enter another
file.
Entry
filename
graphs
are
procedure creates
of a
since
The
time12. To
important data into it for later
and stores all
name of
storage
selection
the Main Menu.
some additional
a special
the
just described for
as
The only difference is that this
display for runtime review.
later date if
are stored
the
an
a normal analysis requires a certain amount of
the
enter
exists will require
is
selection.
video
selection
re-processing the data
needed, the
one of
to the
generated report
selection
same report
retrieval.
filename
which
duplicate filenames
filename is required, use the Delete.File option from the
File Editor/ DOS Utilities selection from the Main Menu to delete the existing file. Upon
are not
If the
allowed.
procedure
completion,
same
program control
This
RECALL Data from File.
This
procedure retrieves
memory in the
processing.
data
stored
proper variables.
Upon
procedure
to
appearance of
access and change
i2The R-wave
peak
the
is
selection
in
a storage
completion,
this
returned
This data
SET: Search/Program Parms.
Menu. The
is
is
shown
process alone requires
item
and places
becomes
selection
search parameters used
detection
action
program control
This
submenu
an
file
now
to the Main Menu.
is
the data in the
for
available
is
the Main Menu.
under
returned
a submenu
to the Main Menu.
item
in Figure E-14. This
for the R-wave
approximately 5-6
peak
computer's
subsequent post
under
submenu
detection
minutes
the Main
to
is
used
procedure.
perform.
APPENDIX E
140
PROGRAM ft PEAK DETECTION PARAMETERS
Voltage Threshold:
.9500
Index Threshold:
256
IHR Patch
20.0000
'/, Band:
Smooth Cutoff Freq.
5.0000
PSD
1.0000
max
Plot Freq.
Figure E-14: The Set Search Parameters
data
during
All
quantities set
the
PSD
To
95
:
Scan Window Size Options:
1024
gives
59
BPM
maximum
512
gives
117
BPM
maximum
256
gives
234
BPM
maximum
128
gives
468
BPM
maximum
window allows adjustment of several parameters
processing.
by
this
Plot Freq.
max
256
to EXIT MENU
<ESC>
used
Scan Window Size:
Zoom Window Size
menu13
were referred
item,
which was
just
to in Sections 2.4.1 through 2.4.3
to in
referred
Section E.5.1
except
137.
on page
for any of these quantities, highlight the selection and press
<RETURN>, this highlights the value itself. Enter the new value and press <RETURN>
again.
this
enter
new
Exiting
Note:
this
be
menu can
values
menu returns program control
through the Main Menu
accessed
a generated report will contain
changed after
data processing, the
will not correspond
are also printed
the
in the
appearance of
new values will
to
the
these
about
be
printed on
obtain
Remember that
parent menu.
as well as
information
actual parameters used
the final
GRAPHING Menu.
quantities.
the
report.
analysis
If they
are
Thus, they
which
results,
report.
SET: PSD Ranges/Labels.
The
to its
this menu,
This
after
selection
the Set
is
item
an action
Frequency
the Main Menu.
under
Band Edges
menu
item has been
for
frequency band #3, is shown in Figure E-15. The bounds of the specific
frequency bands, discussed in Section 2.4.3, are pre-set to the bands normally studied.
However, if new bands or different bands require analysis, the upper and lower frequency
limits of these new bands can be set with the use this submenu. Selecting the number
of frequency bands desired is done using the first selection (Set Number of Frequency
selected
Bands 5). Number entry is performed just as for the previous menu item just described
(SET: Search/Program Parms). A table on the left side of the display (Defined Frequency
Bands)
can
lists the
frequency
current
bands defined. A
maximum of
ten
frequency
bands
be defined.
Set
Frequency
Band Edges. This
selection
is
a submenu
the PSD Ranges/Labels Menu. After item selection, the
for the
number of
number
ure
or
E-15)
l;,The index
zero
at
the
to
frequency band
quit.
the lower
threshold quantity
A
right
here
to be
sub-submenu
corner
was referred
of
the
operator
item
is
under
prompted
adjusted and must enter a valid
will
then
display
to previously
as
appear
and
await
(shown in
fig
modifications
the temporal proximity threshold.
APPENDIX E
141
PSD
Defined
Frequency
5 Bands
are
Frequency
Band Selection Menu
Bands
Defined
Set Number
All Frequencies in Hertz
Band
Band
Lower
Upper
#
Name
Edge
Edge
Set
of
Frequency
Frequency
Bands
5
Band Edges
Set User Band-Ratios
Exit to System
1
VLFP
.0100
2
MLFP
.0400
.0700
3
LFP
.0100
.1500
4
HFP
15-50
.1500
.5000
5
HFP
15-100
.1500
.0400
Change
1.0000
Frequency
Band Number:
Band Name:
Lower Edge:
Upper Edge:
11
SPECTRUM
.0124
25.3924
Figure E-15: The Set Search Parameters
used
during
data
processing.
Band Menu
3
LFP
.0100
.1500
Exit to Main Menu
window allows adjustment of several parameters
APPENDIX E
to the
142
listed.
quantities
Data is
menu returns program control
Bands table is
the
updated with
entered as
to the
relate
to
each
The default
other,
as
the
PLOT AREA: Top.
band
This
PLOT AREA: Bottom.
the Section E.5.1
on
edges are
Full
on
channel
routine can
be
to its
selection
This
This
is
selection
used
in
This
place of
frequency
bands.
is originally compiled
These default
an action
is
is
ratio quantities
Exiting
this
menu
135)
for
item
the Plot All Channels
...
item.
under
this
the Main Menu. See
menu
item.
the Main Menu. See the
under
this
use of
an action
menu
item
use of
item
the Main Menu. See the
under
this
an action
136) for
is
item
use of
an action
selection
for the
parent menu.
selection
Graphic Utilities (page
Display.
this
which
adjustable.
currently
Graphic Utilities (page
Create Multigraph.
Section E.5.1
of
application software.
Graphic Utilities (page 135) for
on
program
the time
at
under
to date.
would return program control
Section E.5.1
the
item
are calculated
analyzed
submenu would allow runtime adjust
frequency
a submenu
ratios
found in the
specific quantities
sufficient
The intended
just
2.4.3,
various
together to form the final
have been
to be
been implemented
not
quantities are established when
and assembled
ratios
in Section
mentioned
Exiting this
Defined Frequency
above.
the
and
menu,
selection was
Ranges/ Labels Menu but has
As
writing.
described
information.
new
Set User Band-Ratios. This
the PSD
parent
menu
item.
the Main Menu.
under
option under
the File
This
Editor/ DOS
Utilities Menu (page
129)
to
this
the
is that only one channel can be displayed at a
dataset is graphed, not just the first 20 seconds worth. That this
procedure and
time,
and
that the
procedure also
view
the
collected physiological
data. The differences between
other mentioned
entire
displays every
eighth point
just
as
the
other channel
graphing
procedures
do.
The filename is
upon
entry
printer.
An
of a valid
upper
about
20 seconds,
display)
is
and
procedure
mentioned
on
page
(less
This
under
be
to
graph
send
some
from
Modify
is
an
immediately displayed
the
Status-Comment
image to the
'panel'
each
display
a nominal
action
graphics
listed file information in the
program control returns
selection
is
Note that
placed on one
a single channel
completion,
131
available
procedure
panels can
display
RESHAPE Acquis. File.
As
is
in Figure 15 (page 58).
that 5
to
option
from this
shown
screens are needed
datafile. Upon
for through the FPW. The
filename. An
example output
left
2-1/2
prompted
represents
screen.
256
Thus,
almost
subfile acquisition
to the Main Menu.
item
#8,
under
the
the Main Menu.
original
acquisition
APPENDIX E
datafiles
143
recorded
To
were supplied.
developed to
the RPW
be together
1,
2
new
and
and
4.
datafile
any time
A
Strangely
data
even
if only two
storage requirements
the file to be
to prompt for
channels of physiological
for these
reduced
is
prompted
which channels
to
extract.
The
to
actual
file
The
operator
has the
option
data
procedure was
file than the
for through the FPW
in ascending order. For
example, channels 1-3
datafile is constructed and the operator is
the original.
files,
this
valid channels and create a smaller
new
replace
prior
the
the data for the
name of
appears
channels of
reduce
extract
The
original.
five
and
then
channels extracted must
or
3-5, but
asked
to
not channels
to verify that the
cancel
this
procedure
replacement.
enough, this
procedure has found use in
subdividing multiple channel ac
datafiles into smaller ones which are able to be transported
using high density
3.5"
diskettes. This is important because a five-channel acquisition file can be as
large
as 2,623,488 bytes in
size, much too large for these 1.44 MB diskettes.
quisition
Manual
IHR:
Compute
HRV
:
Compute
HRV
:
Smooth
HRV:
Window
IHR:
Plot
HRV:
Plot
PSD:
Plot
Press
Figure E-16: The Manual
a vertical space of
Processing
(index)
(smth/wind)
(current)
to EXIT
<ESC>
Processing Commands Menu,
display additional menu
18 lines to
MANUAL: Single Commands.
This
Menu. As
the early
mentioned
cedure operated
continue
to
in Section
level
these
This
procedures also updates
selection
command
specific-procedure
single procedures was made.
ing
E.2,
from the ASYST
allow a
Commands Menu
selected
is
a submenu
versions of
the
item
under
implementation,
STATUS List
Menu, has
the Main
program used single pro
line (from key-combinations
menu provides access
the
from the Main
items.
a menu
to these
with current
actually).
offering the
procedures.
To
original
Implement
processing information.
APPENDIX E
The
144
this
appearance of
EXIT to DOS.
mentioned
the
This
is
operator
response of
or
'y'
EXIT to ASYST.
will exit
used
enter
or
at
to
this level
the direct
the
operator
of
<RETURN> will
This
of
the ASYST
complete
tion
software.
and
layered
the ASYST
this
prevent
program
the
item
an action
level,
return
software
that programming
not
software without
program
'GO'
at
entering
the
operator
designer,
PC
the program,
Only
session.
Menu
items is included
on
an
of
a
the
index
the
If
option
command
primitives or words can
for
an operator
to
primitives usage
perchance events place
command
rate
ASY'ST
ASYST
of
me.
the ASYST
reference,
the
recommended
knowledge
to the Main
convenience and quick
submenu selection
of
the
the Main Menu. This
under
the operating instructions for the heart
For
quit
return
session.
functions. It is
original
and
session
inadvertent termination
to verify the intention to
is
Although
the Main Menu.
under
to terminate the
used
selection
item
action
environment and place computer control at
guidance of
at
an
respond
perform specialized
this level
in Figure E-16.
terminate the
This
the Main Menu
line. It is
be
will
to
is
line. To
command
prompted
'Y'
shown
selection
earlier, this item is
to the DOS
control
is
menu
line
and
pressing
application.
variability
analysis applica
listing of all
following pages.
the Main Menu
Index
Starting
the program,
Stopping
[125]
the program,
The Main
GET: Data
[125, 144]
Menu, left
-
PSD: Plot/smth
(user-fit), [134]
REPORT: Print Cover Page
Utilities, [128, 137]
Plot All Channels
(auto-fit), [133]
column:
Acquisition, [127]
File Editor/DOS
PSD: Plot/smth
20 sec,
REPORT: Print Band Data/Ratios,
[139]
REPORT: List Band Data/Ratios,
[139]
EXIT to
[129]
Data, [134]
DOS, [125, 144]
Edit File
Comments, [129]
Comments, [130]
Modify Status-Comment-#8, [129]
Display File Comments, [130]
Display Subfiles Contained Therein,
The Main
Edit File
(value), [139]
(value), [139]
IHR Patch % Band: (value), [139]
Smooth Cutoff Freq. (value), [139]
PSD max Plot Freq. (value), [139]
Scan Window Size: (value), [139]
Zoom Window Size: (value), [139]
Index Threshold:
SET: PSD
Ranges/Labels, [140]
of Frequency Bands,
[140]
Set Frequency Band Edges (value),
EKG:
Plot, [132]
Main Graphing Menu, [136]
Put Comment, [136]
Print Graph, [136]
MultiGraph, [136]
Set Max Freq., [137, 139]
IHR:
Set Number
[140]
Band Number
(value), [140]
(value), [140]
Lower Edge (value), [140]
Upper Edge (value), [140]
Set User-Band Ratios, [142]
Band Name
Analyze/Find-Peaks, [132]
(time), [132]
PLOT AREA:
[132]
PLOT AREA:
Parse, [133]
HRV: Plot
Parms, [139]
Voltage Threshold:
Channel, [131]
IHR: Patch/Plot,
[139]
SET: Search/Program
_File,
IHR: Plot
column:
file, [139]
STORE Data to File,
Directory D:, [138]
Directory C:, [138]
Directory B:, [138]
Directory A:, [138]
Copy
[138]
Rename-File, [138]
Delete-File, [139]
EKG:
right
RECALL Data from
[131]
Transfer Single
Menu,
Top, [142]
Bottom, [142]
Create Multigraph,
(normal), [133]
145
[142, 136]
APPENDIX E
146
TOP, [136]
BOT, [136]
IHR.T, [136]
HRV (orig.), [136]
PSD, [136]
RESP, [136]
IHR.I, [136]
HRV
(smth/w), [136]
Full Channel
Display, [142]
Process Respiration
Data, [134]
RESHAPE Acquis.
File, [142]
MANUAL: Single
Commands, [143]
Compute, [143, 143]
HRV: Compute, [143, 143]
HRV: Smooth, [133, 143]
HRV: Window, [133, 143]
IHR: Plot (index), [133, 143]
HRV: Plot (smth/wind), [133, 143]
PSD: Plot (current), [143]
IHR:
EXIT to
ASYST, [144]