Download Vagally Induced Second Degree AV Block Mobitz

Vagally
Induced
Mobitz
Type
Second
Degree
A-V
Block
I, and the Hyporeactive
SA
Node*
Miguel
Gambetta,
Iloderick
W.
M.D.,
Childers,
Pablo
Denes,
M.D.,
Second
degree
reflex
the
R
eflex
vagal
stimulation
discharge
prolongs
the
typical
sinus
panied
less
recover
normally
PR
after
of the
We
pacing
vagus
nerve
disrupts
nodal
tion
This
degree
circumstances,
in A-V nodal
rate
while
by removing
cases
responded
poorly
responsiveness
A-V
requests:
60637
cells,
to
This
26-year-old
prosthesis
inserted
of
effect
was
Dr.
obtained
noticed
where
the
the
0.75
mg
resulted
in
in
stimulasecond
the
Childers,
Box
161,
950
East
The
59th
Uni-
patients
by
a failure
of
node.
left
carotid
rate
remained
after
a
sinus
sinus
40
at a rate
massage.
It
unchanged.
and
of the
the
heart
maneuver
in Figure
mm
Hg,
prolongation
The
is shown
administration
Valsalva
is shown
of
rhythm
of 82
of 0.26 sec.
degree
A-V block by right
is shown.
A similar
effect
intravenously
to 0. 19 sec
pressure
a marked
(A)
valve
mitral
and
drug.
rate
is
to
be
effect
of
in strip
C,
The
remained
PR
at
performed
in the
2; after an overshoot
the
sinus
rate
of the PR interval
failed
to
ensued.
2
This is an 18-year-old
The resting
ECG showed
Street,
#{149}j
I I
__
‘‘#{149}‘I’#{149}’’j!#{149}’’
A
Cardiology,
blood
while
top
given
minute
decreased
preserved.
slow
of Medicine,
be
REPORTS
a PR interval
of second
(dark
line)
sinus
of atropine
one
interval
SA
the
82 per minute.
The
effect
of
recumbent
position
vagal
was
at the
during
that
obtained
to reflex
vagal
1 shows
per minute
and
In B, the production
carotid
sinus massage
frequency
reflects
three
to
of the sinoatrial
rate
beats
block.
#{176}Fromthe Department
versity
of Chicago.
Reprint
Chicago
three
discharge
in
appeared
woman
had a Starr-Edwards
mitral
23 years
ago because
of severe
regurgitation.
At the present
time she is asymptornatic
her only treatment
consists
of anticoagulants.
accomtime
produced
effect
1
CASE
The
coordinated
the
I w
this
CASE
vagal
influence,
but preof the A-V node.
Under
A-V
nodal
the
for
the
nodal
the
PR interval
refractoriness.
observed
asymmetry
to depress
and
more
this
type
basis
Figure
atrial
have
A-V
have
Mobitz
The
beat.
of atrial
excitation
from
serving
the responsiveness
these
changes
activity
is not
The
challenged,
each
vagal
block
stimulation.
node
period.
so produced
prolongation.
A-V
vagal
depresses
of the
sinoatrial
nodal
refractory
frequently
Artificial
effect
rate
A-V
bradycardia
by
being
and
M.D.
‘tiI
#{149}#{149}
healthy
a sinus
student
rhythm
I
‘
on no medications.
at a rate of 82 per
J#{149}.
B
C
1. Case
1 : Lead
II rhythm
strips
showing:
( A) control;
( B ) carotid
sinus
massage
by the dark bar),
and ( C ) the effect of 0.75 mgm of atropine
given
mnstravenously.
The PP intervals
are between
700 and 720 msec in the three strips. The PR intervals
are 0.26 sec
during
( A) and 0.19 sec during ( C ). See text for explanation.
FIGURE
( indicated
152
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VAGALLY
INDUCED
SECOND
DEGREE A-V BLOCK
153
VALSALVA
MANEUVER
.5Om
C.)
0)
.8
U)
.7
.4O
.3O
2.
FlGuisx
and
PR
Case
1 : PP
intervals
intervals
are
against
time
neuver.
longation
There
is a marked
of the PR interval
lack of
in
sinus
a
Valsalva
ma-
bradycardia
and
displays
the
.4
proand
I
5
during
phase
IV. The straining
is marked
by a dark bar.
minute,
0
Q.5
plotted
15
10
to
a
sec
Valsalva
( not
shown).
Figure
3
maneuver-development
during
phase IV, the
without
a concomi-
salva
maneuver.
in each
V node
the
14-year-old
of an
healthy
irregular
student
pulse.
had
Figure
an
4 shows
ECG
taken
a continuous
be-
waves
The
of
these
a P wave
of
rates
of
three
per
( below
intervals
configuration
and
patients
sinus
150
A-V
node
was
origin.
minute
They
or
the
all
above,
sec ) when
0.20
axis
of
the
expected
reached
with
P
for
sinus
normal
can
exercised.
reflex
of
the
vagal
the SA
include
bradycardia
bradycardia
normal
cardiac
( when
activity
and A-V
respiratory
30
nodes
are
induced
the
manifestations
of
responsiveness
of
appropriately
balanced)
sinus
arrhythmia,
the
and
is equally
of carotid
sinus
after
the overshoot
massage,
phase
of
and
the
the
Val-
bradycardia
atrial
cyclic
sinus
cases
of
related
the
of
CHEST,
VOL.
62,
NO.
2,
AUGUST
second
that
massage
in
atrial
atrial
fixed
tachy-
frequency
of
excitation.
In
two
of
our
sive
sinus
rate
after
after
node,
the
as
of
vagal
rate
tions
block
in A-V
during
reported
Case
phase
of the
As
during
on
the
was
while
by
sinus
maneuver,
the
A-V
isolated
node
observed
maintaining
respiration,
showed
be
bradycardia
Valsalva
was
in
the
a constant
cyclic
conduction,
and more
carotid
sinus
massage.
2 showed
could
unrespon-
constant
of
a result,
situation
3 who,
the
absence
massage.
A similar
sinus
by
and
stimulation
in case
pattern
a reflexly
evidenced
overshoot
sinus
a similar
1 showed
atropine,
carotid
effect
cases
Case
fluctua-
advanced
A similar
A-V
case
Ehrentheil.2
minimal
and
second
degree
phase
of the Valsalva
slowing
A-V block
maneuver.
of the
II ) obtained
during
the straining
( B ) . Note that the slowest sinue
A-V block developed
(heart
rate
( A ), and after the
rate is 75 per minute
prior to the test was
1972
Downloaded From: http://journal.publications.chestnet.org/pdfaccess.ashx?url=/data/journals/chest/21543/ on 05/02/2017
sinus
node
after
the overshoot
Thus,
in all three
B
3. Case 2 : Selected
strips
(lead
pressure
overshoot
of a Valsalva
maneuver
at the time that first and second
degree
82 beats
per minute).
the
block
#{149}1
FIGURE
in
A-V
paroxysmal
to
Aof
respi-
occurrence
marked
carotid
as
associates,’
.11:
A
seen
pacing
and
The
some
demonstrated.
was
sinus
by
the
block.
cardia
atrial
fixed
from
apparent.
DiscussIoN
the
Feigenbaum
induce
A-V
flutter
or
PR
is
of
degree
patient
Some
.20
.--
25
During
eventuates
strip
(lead
II ) obtained
during
quiet
breathing.
It can be seen
that the sinus rate remains
constant
while the A-V conduction
shows
cyclic
Wenckebach
cadences
occurring
with respiralion.
Inspiration
is indicated
by the dark
horizontal
bars.
Carotid
massage
( both
right
and left)
shown
in Figure
5
failed to induce
sinus bradycardia
while advanced
A-V block
was produced
with two consecutive
nonconducted
P waves.
Comment:
__
I
.
of these
situations,
the vagal
effect
on the
is unrevealed.
When
the input
frequency
ration
3
Thi5
.
20
experiments
cause
I
.
SECONDS
of 0.20
of sinus tachycardia
during
phase II and
production
of second
degree
A-V block
tant sinus bradycardia.
CASE
.
period
a PR interval
response
-.
154
GAMBETTA,
DENES
::
4.
FIGURE
\Iohitz
Case
type
during
3:
Continuous
I developing
expiration.
rhythm
strip
synchronously
Note
the
with
absence
of
respiratory
(lead
II ) showing
respiration.
The
sinus
.Lili_ :
second
degree
“dropped”
AND
beats
CHILDERS
..
A-V
were
block
observed
arrhythmia.
It_
I_
-
5.
FIGURE
A-V
with
during
patients,
vagal
manifest
or more
of the
SA
The
degree
In
to
occur
in
these
node
conduction
in a recent
study.7
speculate
They
to the
other
hand,
be
conceivable
known
SA
as,
for
of
to occur
an
example,
as a result
arteries
of
in
of small
the
in some
in
body
thought
to
in
sinus
nodal
cardiac
cases
vagal
of peripheral
be
an
intrinsic
altera-
properties
of
the
nervous
when
reported
system
and
this
emphasizes
integration
of
the
in its control
the
clinical
system
the
parasym-
of SA and
events
A-V
which
may
is deranged.
REFERENCES
vagal
on
vagal
3
C:
the
Interrelationship
sino-atrial
J Clin
of
pacemaker
Invest
44:399,
Variation
of the
Heart
RL,
findings
in
relation
1952
Averill
KH,
67,375
PR
interval
in sinus
to Wenckebach
Lamb
LE:
asymptomatic
arrhyth-
phenomenon.
Electrocardiographic
subjects.
VII.
Atrioven-
J Cardiol
6: 153, 1960
4 Holmes
JH, Weill DR Jr: Incomplete
heart block produced
by changes
in posture.
Amer
Heart
J 30:291,
1945
5 Benedict
RB, Evans
JM : Second
degree
heart
block
and
with
the
block.
Amer
Wenckebach
or
block.
7 Goldbarg
is
phenomenon
Heart
J 43:626,
6 Harrington
JT,
tricular
in the
diabetic
Fisch
of
conduction.
possible
J 43:229,
its
Johnson
tricular
as
CM,
action
atrioventricular
Ehrentheilof:
mia and
Amer
de-
On
H, Wun.sch
and
1965
innervation
nerve,
here
complex
result
and
recognized
occlusion
and
function
the
disease8
vagus
could
occur.
membrane
phenomenon
nodal
normal
pathologic
Chagas’
cause
not
cells.
potassium
Hirschsprung’s
ac4uired
rate
of 90/mm
P waves
are seen
did
diastolic
1 Feigenbaum
to
91
documented
of the heart.
vessel
the
pathetic
A-V
of the
and
at
an
is postulated
are
rhythm
posi-
Congenital
or absent
result
is
individuals
nature
node.
achalasia
a defective
in
2
have
not
been
vagal
innervation
the
tion
The
degrees
examples,
innervation
of infantile
1 is
of
seen
a sinus
neuropathy.9
An additional
cases,
response
not
on the
the
in parasympathetic
could
nutrient
of
case
disturbances.
uncommon
was
showing
precise
Factors
In
persons
process
strip
made
two
changes
A-V
It
case
number
the
exceedingly
only
other
conduction.
various
on
the
unresponsiveness
the
are
maneuver.
disease.
respect
was
in
hiccups.6
effect
for
can
in
hearts.3
Valsalva
in the
rhythm
unresponsiveness
exhibited
small
this
and
vagal
responsible
fects
II
at the top. At the bottom,
two nonconducted
by a dark bar ) . The expected
sinus
bradycardia
node
the
A-V
of
normal
anxiety,5
is an
as
a
with
increased
One
A-V
by
block
this,
apparently
block
the
in normal
block
associated
as
on
lead
structures,
( marked
massage
A-V
resulted
Atrioventricular
tion,4
carotid
manifest
exercise
be
Continuous
Wenckebach
effect
unexplained.
with
3:
node.
first
known
Case
clinically
Ann
AN,
correlations
Intern
Moran
of
normal
CHEST,
associated
1952
Dc Sanctis
JF,
Childers
exercise
business
Downloaded From: http://journal.publications.chestnet.org/pdfaccess.ashx?url=/data/journals/chest/21543/ on 05/02/2017
anxiety.
RW: Hiccup
induced
Med 70: 105, 1969
multistage
VOL.
with
executives.
62,
NO.
RW,
et
tests
Amer
Amer
atrioven-
al:
Results
in
a
Heart
2, AUGUST
and
group
of
J
79:
1972
VAGALLY
194,
INDUCED
DEGREE
A-V BLOCK
1970
8 Amorin
elevation
Chagas’
DS, Godoy
BA, Manco
in blood pressure
and
disease.
A preliminary
Editorial
This
The
SECOND
1968
9 Fagerberg
SE : Diabetic
logical
study
Med
on
Scand
the
Suppl
neuropathy,
significance
345,
a clinical
of vascular
and
histo-
affections
Acta
1959
Expression
paper
reports
recognition
AV
causes
up
patients.
of these
with
AV
stimulation
and
unusual
unresponsive
node
degree
patients
a rare
of an
responsive
second
JC, et al : Effects
of acute
of atropine
on heart rate in
report.
Circulation
38:289,
155
the
block
me
demonstrate
for
a later
the
reflex
a
develop
of
a
defects?
would
follow-
in life
will
node
syndrome
SA
supraventricular
with
and
vagal
a longtime
time
sick
finding.
node
production
following
to wish
At
SA
the
arrhythmias,
chronic
Clinically,
suggest
the
idiopathic
these
findings
avoidance,
or
and/or
will
AV
conduction
in young
patients
very
cautious
use
of drugs
which
slow
conduction
: digitalis,
dine,
procaine
amide
and the beta
blocking
these
George
they
quiniagents.
C. Griffith,
La Carwda,
M.D.
California
The Tall Grass Called Sugar Cane
Seventy-five
produced
percent
from
latter,
13,746,000
States
102.5
as a table
the
world’s
Saccharum
cane,
tons
in 1970,
with
lb per year.
used
of
sugar
were
a per
Besides
sweetening
sugar
produced
capita
the
and
supply
oljicinale.
in
the
consumption
candy
industry,
flavoring
is
Of the
agent
in
of
is
nation
of
very bitter
hol.
sugar
and
substance
In the refining
acetic
acid
which
process,
anhydride
and as
combi-
results
is used for denaturing
molasses
is separated
in
hours
nea
a
abcofrom
varies
from
three
weeks
Hargrave
and Pepys
(Lancet
a case of bagassosis
that developed
after
exposure
is the
chief
chills,
fever,
is scanty
and
toms
persist
foods,
pharmaceuticals
and beverages
and as a fermenting
agent
in certain
alcoholic
drinks.
It is an ingredient
of a variety
of insecticides,
hair
tonics,
plastics,
photographic
materials,
shoe
polishes
and
explosives.
Too,
sugar
is used
in tanning
leather,
silvering
mirrors,
in adhesives
a core binder
in casting
metals.
Oddly,
chemical
involvement
months.
reported
United
of sugar
sugar
monary
to
moldy
complaint.
retrosternal
mucoid,
bagasse.
It may
pain,
occasionally
1 :619,
four
Usually,
be associated
and
cough.
The
blood-streaked.
to two to three
miliary
nodules
to
many
1968)
to five
dysp-
with
sputum
Sympmonths.
in both
from a few days
X-ray
reveals
widely
scattered
lungs,
unilateral
or bilateral
patchy
infiltrations
in the
upper lobes, or increased
hilar densities
extending
toward
the bases.
Earlier
erroneous
concepts
relative
to its
etiology
have
been
replaced
by authoritative,
precise
knowledge
as formulated
by Buechner
( personal
cornmunication,
February
23, 1.972 ) . “There
is no evidence
sugar.
Also, sugar
cane yields
a valuable
wax, and celbulose which
is used in paper
making
and in synthetic
fiber
manufacturing.
Moreover,
it contains
aconitic
acid useful
in making
plastics.
Bagasse
is the fibrous
residue
of sugar
or silica as playing
a role in the pathogenesis
of this
disease.
It is now well established
that bagassosis
is a
manifestation
of hypersensitivity
to thermophilic
actino-
cane
from
mycetes
organism
after juice
the French
extraction.
The
word
bagasse
is derived
bagage
and
originally
meant
rubbish,
trash
or worthless.
Bagasse
has been
used
as fuel
at
sugar
mills,
for gardening
mulch
and cattle
feed,
in the
manufacturing
of paper,
plastics,
dyes,
acoustic,
sound-
absorbing
boards
which
sugar cane
and refractory
brick.
The plant
from
originated
was a native
of Southeast
Asia.
It reached
it to San Domingo
tropical
United
China
in 100 B C.
in 1493.
It is being
and semitropical
States.
Workers
amounts
of
shipping
and
manufacturing
gassosis.
The
length
CHEST,
bagasse
country
who are
VOL.
62,
dust
in
and
connection
2,
sufficient
AUGUST
brought
in every
the
in
exposed
processes
of exposure
NO.
Columbus
cultivated
to
with
may
southern
massive
handling,
develop
ba-
to cause
pul-
to support
viruses,
toxic
contaminants,
mechanical
irrita-
lion
.
and
is not a fungus
which
produces
the
infection.
The
principle
hypersensitivity
reaction
is
( formerly
known
as Micro-
Thermoactinomyces
sacchari
spora
vulgaris)
but other
thermophiic
actinomycetes
such as Thermoactinomyces
vulgaris
and Micropolyspora
faeni
(formerly
known
as Thermopolyspora
polyspora)
are probably
also involved.”
Heam
and Holford-Stevens
(Brit J md Med 25:283,
1968)
observed
that inhalation
of extracts
of thermophilic
Actinomyces
vulgaris
produced
bate systemic
reactions
typical
of a precipitinmediated
hypersensitivity
response
in 12 of 15 subjects
who had had bagassosis.
Andrew
L. Banyai,
M.D.
1972
Downloaded From: http://journal.publications.chestnet.org/pdfaccess.ashx?url=/data/journals/chest/21543/ on 05/02/2017