- [Voiceover] The other day one of the
pediatric cardiology doctors was joking
around with me and we were talking
about Epstein's anomaly.
He said "I say Epstein's and you say?"
And the answer is Lithium.
So, in the minds of a lot of students
when you're taking tests,
Epstein's and Lithium always go together.
So, the theory is that mothers who take Lithium,
which is a drug to treat bipolar disorder,
that's what leads to their children
having Epstein's defect when they
develop that in the uterus.
Now, according to this doctor I was talking to,
this is just something we've
taken for granted for a long time
and it's not really backed up
with a lot of evidence.
It's just one of those heart defects
we think of as caused
by drugs the mother can take.
But, in reality, it can also happen
in babies whose mothers are not taking Lithium.
So, Epstein's is a defect that
involves the right side of the heart.
We have our right atrium, right ventricle,
down here, left atrium, left ventricle,
blue pulmonary artery, red aorta.
So, in Epstein's we have something happening
in the tricuspid valve,
which is usually here,
between the right atrium and right ventricle.
And it basically drops downward.
We call it displaced.
It's almost like it has fallen off
towards the ventricle.
So, the way I'm drawing this,
it's going to look really awkward
because I'm trying to modify,
instead of redrawing this thing.
It's just to show you the right atrium
extends down here, now.
So, the right ventricle is still
connected to pulmonary artery,
but now, the right ventricle is tiny.
It's this area down here.
And the tricuspid valve, again,
it's between these two chambers.
But, it's usually underdeveloped or floppy
or something is wrong with it.
There's a word associated with Epstein's.
We call it the "atrialization"
of the right ventricle.
Let's see if I can spell that,
a-trial-ization.
It basically just means because the tricuspid valve
that separates the two drops down,
then this whole area above
that used to be the right ventricle,
or is supposed to be, now is the atrium.
So, the atrium is bigger, the ventricle is smaller.
This makes the right ventricle pretty wimpy.
It's small and weak.
Now, let me come in and draw
the septum between the right and left atrium
that separates the two top chambers.
In as many as half of the people with Epstein's,
there's a whole between the right and left atrium.
So, we have our atrial septal defect
or ASD.
De-fect.
Okay, so this is how Epstein's is set up.
The left side works the same.
So, red blood comes back in
to the left atrium from the lungs
and the left ventricle pumps it to the aorta.
So, why do we have cyanosis?
Let's start from the beginning.
When this baby is first born,
keep in mind that when the baby's first born
the lungs have very, very high resistance.
As much as four times the amount
of resistance that adults have.
So, in our pulmonary artery, here,
we got a huge force going this way.
So, if your drop of blood, deoxgenated blood,
from the body going into the right atrium,
which is now huge,
go to the right ventricle.
If a choice between going
into the pulmonary artery, here,
or going back through the tricuspid valve.
Let me just label that really quickly.
Tricuspid.
Remember that it's dropped down
and it's not working perfectly.
So, the blood can't actually get back
behind the tricuspid valve, back into the atrum
and go across, shunt across,
to the left side, here.
So, especially in the beginning of life
with this high pulmonary resistance,
the blood favors this route going to the left side.
So, we have a big strong shunt this way.
This results in the left atrium
having, again, mixed blood.
So, we have blue from the right side
and red coming from the lungs
and we got purple blood going
into the left ventricle
and purple blood going out to the aorta.
So, cyanosis from this mixing,
also, from the fact that we're not getting
too much blood to the lungs.
So, you remember from this particular way of shunting,
we can kind of think of the right atrium
or right ventricle as just one blob of things.
The valve, here, is not working too well
to keep it two separate places.
So, as the wimpy right ventricle tries to squeeze
whatever power it can generate,
it usually pushes the blood over to the left side,
instead of through this
high-resistance pulmonary artery.
Now, as soon as the baby is born,
the resistance in the lungs begin to drop.
So, this might be the one disease
that actually gets a little better
as this child gets into the first few weeks of life.
So, I just erased the arrows,
talking about our resistance
and with that the size of the shunt
gets a little smaller.
So, there's still some shunting.
And redraw the arrow like that.
There's still some shunting.
But now, we got more blood go
into the pulmonary valve,
as the resistance in the lungs keep dropping
until it's at a normal adult level,
then more and more blood will go into the lungs.
So, this disease actually gets better
as the kid gets older.
Because all we care about is the resistance
in here dropping enough,
so that most of the deoxygenated blood
goes to the lungs instead of to the left side,
then we have less mixing
and that will give the left side
more red blood instead of purple.
And that's basically all we care about
is, functionally, how strong the shunt is.
So, as long as most of the blood is going to the lungs,
then we're okay.
Not to say that people with Epstein's don't need
surgery or treatment because most of the time
they don't just have Epstein's.
They have something else that might need to be repaired.
But, as far as, this particular thing
we've talked about,
remember that it get's better
as the pulmonary resistance drops.
And there's a chance that this child
might get away without surgery.