Partial Zone of Apposition Closure in Atrioventricular Septal Defect: Are Papillary Muscles the Clue

This uncommon form of atrioventricular septal defect is identifiable with echocardiography and may be associated with significant postoperative regurgitation if the zone of apposition is completely sutured at time of repair. Limited closure of the zone of apposition may improve postoperative regurgitation.