Atrioventricular septal defect with communication at the atrial level only (Q46192)

A congenital cardiac malformation that is a variant of an atrioventricular septal defect (atrioventricular canal defect) with an interatrial communication just above the atrioventricular valve, no interventricular communication just below the atrioventricular valve, separate right and left atrioventricular valvar orifices, and varying degrees of malformation of the left sided component of the common atrioventricular valve. Additional information: the bridging leaflets of the common atrioventricular valve are bound down to the crest of the scooped out ventricular septum so that the potential for shunting through the atrioventricular septal defect is possible only at the atrial level and not at the ventricular level.