When a remnant of the interventricular membranous septum is also present, the so-called membranous flap, it lies immediately on top of the atrioventricular bundle.
This ring, as well as being interventricular, is also atrioventricular at its initial location within the inner curvature of the heart.
The interventricular grooves are shallow and identifiable only by the courses of the interventricular coronary arteries.
At this point, the exact dimensions of the patch required to cover the interventricular communication can be evaluated exactly.
In such patients, the interventricular defect is usually small, and shunting is limited by tendinous cords tethering the bridging leaflets.
In many patients, however, the diameter of the interventricular communication is smaller than the diameter of the arterial orifice to which it is connected.
One group had an interatrial shunt constructed, the other had an interventricular shunt constructed.
An interventricular communication, however, was described in a single case in the literature3 and was seen in the present case.
