Fetal Echocardiography

Double Outlet Right Ventricle with Transposition

So those can certainly coexist.

Now, if the aorta can move rightward,
and overly of ESD, it is possible for the aorta
to actually move so far, rightward
that it actually originates from,
the right ventricle as well.

And this is just a severe form of aortic overriding,
and known as a double outlet, a right ventricle.

And a lot of times when this occurs,
there can be transposition,
of the great vessels as well.

And so this is one where the aorta is coming out
anterior to the pulmonary trunk.

So this is a double outlet, right?
Ventricle with transposition,
and that's a very common association as well.

Schematics and Ventricular Arterial Connections

Okay. And then this is,
schematics basically showing this,
ventricular arterial connections.

And these are outflow track type VSDs.

When we have a transposition, the aorta
and pulmonary artery will be parallel to each other.

Unfortunately, that happens in textbooks,
but it doesn't always happen in real life.

And frequently there's other more complex cardiac defects
that obscure, this parallel arrangement of the aorta
and pulmonary artery,
because looping hasn't occurred properly
and the orientation of the heart may be wrong.

So we may not see the classic, abnormality.

The key thing to diagnose transposition is to recognize
that the aorta is coming off to the left
of the pulmonary artery now rather than the other way
around, which is appropriate.

Video Descriptions of Transposition

And On this video,
I think you can see, well, it's very fast.

There's only one ventricle here, really.

And so both outflow tracks are coming off the one ventricle.

And on this video loop we're starting off,
here's superior vena cava coming into atrium.

And then you can see the aorta coming off here.

And this is really coming off the right ventricle,
and you'd have to be oriented, see other views to know this.

But that is really what tells us that.

There's a transposition here, as well
as a double outlet, ventricle.

We're not seeing the other outflow tracked here,
on this particular video loop.

Here's a four chamber view,
and as we sweep through this up,
now you can see there's one outflow
and here's the other outflow.

And they're both coming off the same chamber,
which is really the right ventricle.

I know this is very fast,
but, that's really what we're looking for here.

So not only is there a double outlet ventricle here,
but these are transposed
because the aorta is coming off to the left
of the pulmonary artery.

Okay? And this is what we're showing here.

This is the anterior, aorta.

So this is a transposition.

And then here, when we're do an angiogram,
the left ventricle are pacified,
and yet it fills the pulmonary artery.

That by definition is transposition.

And then here's one, here's a transposition.

You can see the aorta is to the left
of the pulmonary artery.

Pulmonary artery coming off, left ventricle,
aorta coming off right ventricle.

And that's a transposition of the great vessels.

Types of Transposition of the Great Vessels

Now transposition of the right ve of the great vessels,
comes in two varieties, the d transposition
and L transposition.

D-Transposition

And the dfor is really when the, outflow tracted
and the arteries have actually switched.

And this is abductus dependent lesion,
because you have two parallel circuits
that are not connected to each other in any way.

So blood flow comes out the left ventricle,
it goes out the pulmonary artery
and then comes back the pulmonary veins back
to the left atrium, and to the left ventricle.

So you have circulation of blood,
from the left ventricle back to the left ventricle,
and there's no intermixing here on the right side.

The systemic side,
blood flow is coming out of the right ventricle.

It comes out the aorta, goes to the body, comes back
through the superior and inferior vena cava into the right
atrium, and then it's into the right ventricle again,
and now it's going out to the body.

So you have systemic flow
that's completely separate from pulmonic flow.

And so you need either A VSD or you need a paint
and ductus arteriosis
to connect these two systems to each other.

So this defect can lead to some of the worst forms
of cyanosis and high hypoxia, postnatally,
of any of the defects.

L-Transposition

Now, the l transposition is less severe.

That just means the ventricles are switched,
but the rest of the circuit actually is normal
and they're insist they're not in parallel,
they're actually, in connection.

And, these don't result in, the degree of hypoxia
that the detransposition, results in.

Additional Views and Diagnosis of Transposition

And so this is a transposition.

So you see this is the aorta coming off the right
ventricle and you can see that.

And then this is a little harder to see.

Here's the pulmonary outflow tract here and here,
and it's very unusual to actually see the bifurcation into
the right and left main pulmonary artery.

This tells us the alignment is abnormal anyway,
and this is coming off the left ventricle.

So this is, as we sweep through,
you can see right ventricle aorta,
left ventricle pulmonary vessels.

And the best way, and there's even a little VSD here,
the best way, to make this diagnosis is to do sweeps
through the heart and then go frame by frame
and determine which outflow tract is connected
to which ventricle in this particular case,
this VSD is necessary
because this is what connects the two circulations
to each other and allows oxygenation of the neonatal blood.

And here's just another view of this aorta,
coming off the right ventricle.

And here's the pulmonary artery,
and this is left and this is right.

So these are transposed
and you really have to look at these very carefully
and figure out what's connected to
what they're very difficult to see otherwise.

Okay? And this is, a schematic of that.

Severe Aortic Overriding and Truncus Arteriosus

And this is just a severe aortic overriding, over A VST.

And in this particular case,
only one outflow tract is formed.

There's not a separate aorta
and a separate pulmonary artery,
and that's a truncus arteriosis.

Screening for Outflow Tract Abnormalities

So these are the outflow tract abnormalities.

These are the most difficult ones to diagnose.

Our job when we screen for these defects is strictly
to determine if there's reversal flow in the
ductus or the aorta.

And that will tell us whether this is a lethal defect,
and whether further evaluation is needed.

And then these can be referred to the appropriate center
where these are gonna be treated post postnatally.

And again, this is a schematic showing various types
of truncus defects.

And a lot of combinations are possible.