Cor triatriatum associated with total anomalous pulmonary venous drainage in the setting of mitral atresia and a restrictive interatrial communication.

A rare variant of cor triatriatum is described in which the proximal "accessory" chamber received all four pulmonary veins and drained into the levoatriocardinal vein and then into the innominate vein. The distal "true" chamber contained the left atrial appendage. The left atrioventricular valve was atretic and the interatrial septum was restrictive.