Transitional atrioventricular septal defect Inclusion term(s):Intermediate atrioventricular canalIntermediate atrioventricular septal defectIntermediate endocardial cushion defectOstium primum atrial septal defect (type I) with separate atrioventricular valves and a small or restrictive inlet VSDTransitional atrioventricular canalTransitional endocardial cushion defect