“Clinical Presentation of Congenital Heart Disease: Congestive Heart Failure” by Michael Freed, MD

“Clinical Presentation of Congenital Heart Disease:  Congestive Heart Failure” by Michael Freed, MD

Clinical Presentation of Congenital Heart
Disease in the First Week of Life: Congestive Heart Failure, by Dr. Michael Freed. My name is Michael Freed and I’m a Pediatric
Cardiologist at Boston Children’s Hospital and at Harvard Medical School. And I want to spend a little time today talking
about congenital heart disease in the newborn period. Introduction. Children come in in the first week of life. They present in one of four ways. With a heart murmur, with an arrhythmia, congestive
heart failure, or with cyanosis. So let’s talk about congestive heart failure. Congestive heart failure is an inability of
the heart to do the work that’s required, and the signs and symptoms that come because
of that inability. There are two conceptual reasons why you might
have difficulty. The first is that there is something wrong
with the heart muscle. You have a normal amount of work. But somehow the muscle just isn’t strong enough
to do the work. The second is that you have a normal muscle,
but you’ve put too much of a workload on it. So if there was a weight on the table in front
of me, if there was a 5 pound weight and I couldn’t do it, there’s something wrong with
me. If there’s 1,000 pound weight, I just can’t
do a 1,000 pound weight. If you looked around our ward, I think you
would say that the structural problem, too much work with normal muscle is much more
common. I’m not so sure that’s the case. Fetal Development. I think that almost all of these are genetic
defects. And I suspect there are just as many genetic
defects in the mitochondria and energy transport systems as there are causing structural heart
disease, but we just don’t see them. Where are they? Well, I think they don’t survive fetal life. I think that you can be born without kidneys,
you can be born without lungs, you can be born without a large part of your brain. But once you have an embryo that’s more than
four cells thick, you need some way of getting nutrients inside to the cells and get waste
products out. So once an embryo is more than four cells
thick, you need some type of circulatory system. And in fact, in the human, there’s a primitive
straight tube that develops by 27 days after conception that’s actually doing the work. And if there’s something wrong with that tube,
if there’s something wrong with the muscle, they just don’t survive fetal life. So I think a lot of first trimester abortions
may very well be heart muscle problems that we’re not seeing. And the rest of fetal life selects out for
those, leaving just the ones with normal muscles, but structural problems. And the corollary to that is that the things
that we’re seeing at birth are in fact things that work in utero. Otherwise, they wouldn’t survive fetal life. And what happens is that I think that the
fact that the circulation is arranged in parallel rather than series allows a whole group of
very complicated diseases that work in the newborn period, but once you go into that
in the series circulation, don’t work after you’re born. So I think this presentation of babies in
the first week of life are kids that worked in utero, but don’t work when they’re born. And I think there’s a comparable group that
doesn’t work in utero that we’re not seeing, and a lot of those have muscle problems. Structural Heart Disease. So if we have a baby with congestive heart
failure– he doesn’t have a muscle problem, he’s got some structural problem, too much
work for a normal muscle. And remember, we said the work of the heart
is pressure and volume, so there must be either too much pressure work or too much volume
work. If you look at the first month of life, I
think that most kids who come in would be too much volume work. Ventricular septal defects, single ventricles
without pulmonary stenosis, truncus arteriosus, the whole variety of things. But we don’t see those in the first week of
life. In the first week of life the pulmonary vascular
resistance is still quite high. And it prevents enough of a left-to-right
shunt through the VSD, or the single ventricle, or the truncus to give enough of a volume
overload to cause congestive heart failure. So if our talk is heart failure in the first
week of life, which is what we’ve started the premise, then we’re dealing not with muscle
disease, not with volume overload, but just pressure overload lesions. And if you look at the pressure overload lesions,
aortic stenosis, pulmonary stenosis, coarctation, and hypoplastic left heart syndrome. And I’m going to make it even easier. Pulmonary stenosis doesn’t fit here. If we’re talking about heart failure, tachypnea,
tachycardia, not feeding very well, sweating– that’s not the way pulmonary stenosis presents. If you look at pulmonary stenosis, these kids
have severe right ventricular outflow tract obstruction. The right ventricle has to generate a higher
pressure to pump blood out. And if it starts having difficulty generating
that higher pressure, by Starling’s Law, it increases preload. If you increase the preload in the ventricle,
the atrial pressure goes up. And in the newborn period, if the right atrial
pressure exceeds the left atrial pressure, you start shunting right-to-left and you end
up with cyanosis. So kids with severe right ventricular outflow
tract obstruction from pulmonary stenosis present with cyanosis, not with congestive
heart failure. So now we’re essentially down to three diseases
in our differential diagnosis of heart failure in the newborn period. And how can we tell these apart? Well, coarctation– now, the difference in
pulses or blood pressure should work. That is, before the ductus closes they’re
not sick. But if these kids are sick, the ductus must
have closed and now they must have a pressure gradient. So just feeling pulses or measuring pre- and
post-ductal blood pressures should diagnose coarctation for you. In neonates with coarctation of the aorta,
the strength of the pulses in the lower extremity will be reduced or absent in comparison to
the pulses in the upper extremity. Pre- and post-ductal blood pressure examination
will reveal a discrepancy between the right arm– which is pre-ductal– and the leg–
which is post-ductal– blood pressures, with a higher systolic blood pressure in the right
arm when compared to the legs. Typically, a discrepancy of greater than 20
millimeters of mercury in the systolic pressure measurement is considered significant and
should prompt further workup for coarctation. To separate out aortic stenosis from hypoplastic
left heart syndrome get an electrocardiogram. These kids have LVH. These kids have no LV. And that’s the differential diagnosis of heart
failure in the newborn. This concludes our video on Clinical Presentation
of Congenital Heart Disease in the First Week of Life: Congestive Heart Failure. Thank you. Please help us improve the content by providing
us with some feedback.