00:00
fatal in early childhood.
All right, so let’s start by talking about
obstructive lesions. These are lesions that
impair the forward blood flow out of one of
the ventricles. There are three common ones
- pulmonic or pulmonary stenosis in which
the pulmonary valve is abnormally formed and
consequently, the right ventricle is usually
hypertrophied, it has a much bigger workload,
and often, the blood flow into the lungs is
reduced. If this is very severe, it has to
be dealt with in very early childhood, often
with a balloon catheter that dilates up the
pulmonic valve. Later, the valve may need
to be replaced if it scars down a lot. The
same thing can happen to the aortic valve.
00:43
It can be born too small and again, this leads
to marked decrease in the blood flow into
the whole body and again, often requires a
balloon catheter opening of the aortic valve
in early life and again often down the road,
you need to replace that valve as it scars
down. Coarctation of the aorta is an obstruction
that occurs in the aorta where the aorta is
markedly narrowed in one place and again,
causes decreased blood flow to the lower extremities
and to the abdominal organs and consequently,
one has to open that, sometimes with a balloon
catheter treatment, sometimes with surgery.
We’re going to talk about these in a little
more detail.
Let’s talk about pulmonary stenosis. As
I mentioned before, the right ventricle has
to hypertrophy - has to get bigger and thicker
because it’s facing a big increase in its
afterload, in its work. This is… can lead,
of course, eventually, to right ventricular
failure. Often the pressure is quite low in
the lung and the blood flow is quite low in
the lung and you may even see, in early life
or later life, you may actually see right
ventricular failure with edema, with swelling
of the abdomen and the legs. Again, this lesion
creates a very nice, loud murmur. So, it’s
very frequently picked up in childhood and
taken care of. If it’s mild, it’s just
followed. If it’s severe, a balloon catheter
is put in and expanded and opens the pulmonic
valve. It makes a murmur like the one with
aortic stenosis. You hear… have turbulence
during systole, during the contraction of
the right ventricle and you hear, “shoo,
shoo, shoo, shoo,” over the pulmonic valve.
Aortic stenosis, similarly, is a lesion that
affects the left ventricle. Left ventricle
also hypertrophies, gets thicker because it
has to push harder to get the blood out into
the aorta, can also be associated with decreased
cardiac output, decreased blood flow and even
needs operation or a balloon opening of the
valve in very early postnatal life that is
soon after the baby is born. If the aortic
stenosis is very severe, it has to be opened by
a balloon catheter or the infant won’t survive.
03:06
Again, it produces a systolic murmur. Each
time the ventricle squeezes, you hear, “zhoot,
zhoot, zhoot,” as the turbulent blood flow
passes through the stenotic aortic valve.
03:20
Coarctation of the aorta is an interesting
one because it’s often missed. The coarctation
occurs just after the arch of the aorta and
consequently, leads to increased blood pressure
just behind it so there’s increased
blood pressure in the arteries of the arms
and the arteries of the head and there’s
decreased blood pressure in the legs. So there’s…
and also, of course, a characteristic murmur.
So, this may be missed by the doctors because
we usually take the blood pressure on the
arm. So, the blood pressure might be a little
elevated, but often you don’t take the blood
pressure in little kids and they can have
fairly normal development. I’ve even seen
patients get into teenage years or even older
when suddenly, the heart began to have trouble
keeping up with this increased workload. Patients
may have been a little short of breath, they
may have been a little fatigued or they may
be without symptoms, but it was picked up,
as I’m going to show you in a moment, by
a characteristic finding on the x-ray. The
treatment is either balloon opening of the
narrowing or operation in which the stenotic
or narrowed segment is removed and a graft
is placed in there. This lesion is often associated
with a systolic murmur heard best over the
spine. Why? Because the aorta runs along the
spine as it… after it follows the arch and
consequently, you may just hear a nondescript
little systolic murmur in the front of the
heart whereas when you listen in the back
of the heart, over the… over the chest,
you may hear a louder murmur. The clue is
that you have nice, bounding pulses in the
arms and almost no pulse in the legs and you
say, “How come I can feel a bounding pulse
in the arms, I can’t feel it in the legs?”
And then, often, a chest x-ray gives you the
answer. This is one of the correctable forms
of high blood pressure. Most patients with
high blood pressure don’t have correctable
forms, but this is one of them. And interestingly
enough, even after correction, there’s a
tendency for the patient to develop high blood
pressure that needs drugs to be taken care
of. As I said before, it’s due to a congenital
narrowing in the aorta, which sometimes slips
past the pediatricians and we see these patients
in adult life when they end up with hypertension.
Now, here is the finding that often is most
embarrassing to the cardiologist. Maybe you’ve
seen a patient because they had a little hypertension,
and you’ve been asked they’re going to
have a hernia repair or some minor surgery
and you’ve been asked to clear them. “Yes,
their heart’s okay. They’ll withstand
the operation.” And then in the preoperative
chest x-ray, the radiologist calls up with
a great, big laugh and says, “Hey, did you
guys know your patient has coarctation of
the aorta?” How does the radiologist know
that? Because when there’s coarctation of
the aorta, there’s large number of collateral
or reserve blood vessels that open up. Some
of these are underneath each rib and what
they do is cause… you can see this little
notching, this little cavity on the underside
of the rib. That’s a characteristic of the
collateral blood vessels. It’s picked up
on the chest x-ray and if you hadn’t thought
the patient had coarctation, it’s rather
embarrassing that the radiologist gets to
make the diagnosis. If you thought coarctation
might be there and you ordered the chest x-ray,
that’s okay. But, there’s a significant
number of these folks, usually without severe
coarctation who slip through into adult life.
If the coarctation is very severe, it’s
almost always picked up in the pediatric period
of time.
07:06
So, now, we’re going to deal with lesions
where there’s a hole in the heart. These