Atrioventricular septal defect with an imperforate right-sided component of the common atrioventricular valve: anatomic and embryologic considerations.

We describe an atypical case of an atrioventricular septal defect with a common atrioventricular junction in which the right-sided component of the common atrioventricular valve was imperforate, producing tricuspid atresia with a severely hypoplastic right ventricle and an ostium primum defect. We discuss the implications of the anatomic findings with regard to concepts of cardiac development, drawing a comparison with similar cases previously reported.