Download Ventricular diastole- Form and Function

Aristotle once put forth the proposition that women had less teeth than men.
Aristotle could have avoided the mistake of thinking that women have fewer teeth than men, by the
simple device of asking Mrs. Aristotle to keep her mouth open while he counted.
Bertrand Russell (1872-1970), British philosopher, mathematician. Unpopular Essays, "An Outline
of Intellectual Rubbish" (1950).
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counts. II
learned
learned very
very early
early the
the difference
difference between
between knowing
knowing the
the
name
”
something.
name of
of something
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and knowing
knowing something.”
something.”
Ventricular
Ventricular diastolediastoleForm
Form and
and FunctionFunctionConcept
Concept and
and Review
Review
Richard
-1988
1918
Richard Feynman
Feynman 19181918-1988
Sándor J Ková
Kovács PhD MD
Cardiovascular Biophysics Laboratory
Washington University St. Louis
NASCI 10/05/09
NASCI 10/05/09
Ventricular filling: form and function
Ventricular filling: form and function
The
The physiologic
physiologic process
process by
by which
which the
the heart
heart
fills
has
confused
physiologists,
biomedical
fills has confused physiologists, biomedical
engineers,
engineers, cardiologists,
cardiologists, medical
medical students
students for
for
generations.
generations.
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**Page
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163
NASCI 10/05/09
Ventricular filling: form and function
NASCI 10/05/09
Ventricular filling: form and function
The
The recent
recent recognition
recognition that
that up
up to
to 50%
50% of
of
patients
admitted
to
hospitals
with
patients admitted to hospitals with the
the
diagnosis
diagnosis of
of congestive
congestive heart
heart failure
failure (CHF)
(CHF)
have
normal
systolic
(emptying)
have normal systolic (emptying) function
function has
has
further
further emphasized
emphasized the
the need
need to
to more
more fully
fully
understand
understand the
the physiology
physiology of
of diastole
diastole (filling).
(filling).
NASCI 10/05/09
In
In an
an effort
effort to
to better
better understand
understand the
the filling
filling
process
process cardiologists
cardiologists have
have noted
noted certain
certain
relationships
relationships between
between pressures
pressures in
in the
the atrium
atrium
and
and ventricle
ventricle and
and transmitral
transmitral flow,
flow, motion
motion of
of
the
the mitral
mitral annulus,
annulus, atrial
atrial function
function etc.
etc.
NASCI 10/05/09
Ventricular filling: form and function
Ventricular filling: form and function
Pericardial anatomy
Anatomy and terminology
NASCI 10/05/09
Ventricular filling: form and function
NASCI 10/05/09
Ventricular filling: form and function
Anatomy
Anatomy
NASCI 10/05/09
Cardiovascular
Cardiovascular Anatomy
Anatomy and
and Physiology
Physiology
NASCI 10/05/09
Ventricular filling: form and function
LV gram via 6F pigtail catheter
Cardiac MRI Cine Loop
‘fourfour-chamber view”
view”
(Courtesy CMRL)
“So let's look at the heart and see what it's doing -- that's what counts. “
NASCI 10/05/09
NASCI 10/05/09
Ventricular filling: form and function
Cardiac MRI Cine Loop
‘shortshort-axis view”
view”
Ventricular filling: form and function
Cardiac MRI Cine Loop (Courtesy CMRL)
“shortshort-axis (salami slices) view”
view”
(Courtesy CMRL)
NASCI 10/05/09
NASCI 10/05/09
Ventricular filling: form and function
Ventricular filling: form and function
The cardiac cycle as
taught in a textbook
of medical physiology
Simultaneous, high
fidelity LAP, LVP and
transmitral Doppler
in closed chest canine.
Note reversal of sign of
A-V pressure gradient
As flow accelerates
(LAP > LVP) and
decelerates (LAP < LVP).
________
Isovolumic
Rapid
Relaxation
Filling
Diastasis
Atrial
Systole
NASCI 10/05/09
What
What Happens
Happens in
in Diastole?
Diastole?
Mechanics of filling:
filling
Ventricle fills in 2 phases:
1) Early rapid filling (dP/dV< 0)
2) Atrial filling (dP/dV > 0)
LA
RA
LV
RV
NASCI 10/05/09
Ventricles fill in two stages (E(E-and AA-waves)
Ventricular volumes enlarge as blood enters from
atria resulting in elongation of ventricles and
ventricular wallwall-thinning
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(Diastole has 4 phases: isovolumic relaxation, early rapid filling,
filling, diastasis,
atrial contraction)
NASCI 10/05/09
Model of suction initiated filling:
filling
How
How the
the Heart
Heart Works
Works When
When itit Fills
Fills
Mechanical analogue to account for diastolic suction
We all agree that:
c
k
m
At mitral valve opening, and for a little
while thereafter,
the LV simultaneously decreases its
pressure while increasing its volume!
x(t), F(t)
Newton’s Law: m d2x/dt2 + c dx/dt + k x = 0
Initial conditions: x(0) = xo ⇒ stored elastic strain powers suction
v(0) = 0 ⇒ no flow prior to valve opening
Compare model predicted velocity of oscillator to
velocity of blood entering the ventricle through mitral valve.
Therefore it is a mechanical
SUCTION PUMP!
NASCI 10/05/09
NASCI 10/05/09
Mechanics of filling:
filling
How
How the
the Heart
Heart Works
Works When
When itit Fills
Fills
We summarize : to explain the contours
of clinically observed Doppler EE-waves
we utilize the heart’
heart’s role as a suction
pump whose kinematics can be modeled
as a Simple Harmonic Oscillator (SHO)
driven by a linear, bibi-directional spring!
Given:
Another basic attribute about how the heart works:
The heart is a constant volume pump!
NASCI 10/05/09
How
How the
the Heart
Heart Works
Works :(:(constant
constantvolume
volume))
How
How the
the Heart
Heart Works:(
Works:(constant
constantvolume
volume))
Plot of # of voxels vs. fraction R-R interval for 3-D data set
Constant volume attribute of the fourfourchambered heartheart-
1000
Ê Hamilton and Rompf -1932
Diastole
Systole
LV + LA
RV + RA
Ao + PA
Pericardium
800
Hamilton W, Rompf H. Movements of the Base of the Ventricle and the Relative Constancy of the Cardiac Volume.
Am J Physiol. 1932;102:559-65.
Voxels
Ê
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Ê Hoffman and Ritman -1985
Hoffman EA, Ritman E. Invariant Total Heart Volume in the Intact Thorax. Am J Physiol. 1985;18:H883-H890.
Also showed that Left and Right sided parts are constant volume.
600
400
200
0
0.0
0.2
0.4
0.6
0.8
1.0
Fraction of R-R Interval
NASCI 10/05/09
NASCI 10/05/09
How
How the
the Heart
Heart Works:(
Works:(constant
constantvolume
volume))
Constant-Volume Attribute of the Four-Chambered Heart
Via MRI - how are images analyzed? (with Bowman, Caruthers, Watkins)
How the Heart Works:(constant volume)
Cine MRI loop of pericardium for one cardiac cycle
Conclusion: In normal, healthy subjects, the total volume enclosed
within the pericardial sack remains constant to within a few percent.
The pericardial surface exhibits only slight radial displacement
throughout the cardiac cycle most notably along its diaphragmatic
aspect.
NASCI 10/05/09
How
How the
the Heart
Heart Works:(
Works:(constant
constantvolume
volume))
Right heart vs. left heart (n=20)
1
Left
Right
Pericardium
0.6
0.4
0.2
0
0
0.2
0.4
0.6
0.8
1
% of cardiac cyc
Average Short Axis Ventricles
1.2
1
0.8
Left
Right
Pericardium
0.6
0.4
0.2
0
0
0.2
0.4
0.6
0.8
CONCLUSIONS:
The
The 'constant-volume
'constant-volume pump'
pump' and
and 'suction
'suction pump'
pump' attributes
attributes
of
of the
the heart,
heart, when
when modeled
modeled correctly
correctly predict
predict and
andexplain
explain
the
the observations
observationspertaining
pertainingto
to why:
why:
1)
1) E/E’
E/E’isis aa legitimate
legitimate index
index of
of diastolic
diastolic function,
function,
2)
2) E/E’
E/E’isis linearly
linearly related
related to
to LVEDP,
LVEDP,
3)
3) the
the relationship
relationship of
of maximal
maximal rate
rate of
of wall
wall thinning
thinning
to
to the
the Doppler
Doppler E-wave
E-wave
and
and
4)
4) We
We can
can now
now solve
solve the
the ‘Load
‘Load Independent
Independent Index
Index
of
of Diastolic
Diastolic Function”
Function” problem!
problem!
Average 4 Chambe
1.2
0.8
NASCI 10/05/09
1
% of cardiac cycle
NASCI 10/05/09
NASCI 10/05/09
Ventricular Diastole - Form and Function Concept and Review
How the Heart Works:
Acknowledgement of support and participants:
participants:
Support: Whitaker Foundation, AHA, NIH, BJH Auxiliary, Alan A. and Edith L. Wolff Charitable Trust
Mike Courtois,
Stefan Fischer,
Christine Lorenz,
Faculty:
Faculty: Ben Barzilai,
Phil Ludbrook,
Julio Pé
Pérez,
Fellows:
Fellows: Mike Hagley, Dave Prewitt, Jasvindar Singh,
Students:
Students: Undergrads Scott Nudelman,
Mike Rich ,
Sam Wickline,
Danielle Cook,
Alex Waters
Jon Milde,
Abby MansonManson-McGuire, Stephanie Eucker,
Raj Shani,
Amy Nichols,
Grad Students:
Andy Hall,
Julia Bettlach,
Tim Meyer,
Randy Setser,
Murielle Launay,
Yue Wu
Mark Sessoms,
Danielle Cook,
S. Gazula,
Melanie Kotys,
K . Lakshminarayan,
THE END
Medical and MST P* Students: Nathan Stitziel, Joe Aranowitz, Drew Bowman*
and More:
More: Peggy Brown; Jennifer Lisauskas, BJH Cath Lab Staff
NASCI 10/05/09
NASCI 10/05/09