Transitional atrioventricular septal defect

**Inclusion terms:** - Intermediate atrioventricular canal - Intermediate atrioventricular septal defect - Intermediate endocardial cushion defect - Ostium primum atrial septal defect (type I) with separate atrioventricular valves and a small or restrictive inlet VSD - Transitional atrioventricular canal - Transitional endocardial cushion defect