An unusual type of anomalous pulmonary venous drainage associated with a complex left heart hypoplasia and a variety of divided left atrium ("cor triatriatum").

A previously unreported complex congenital cardiac malformation was noted in which a vestigial left atrium consisted of two completely separate portions, one of which was connected to the pulmonary veins but had no outlet orifice. The pulmonary venous drainage was through an anomalous intrapulmonary vein within the displaced right lung into the inferior caval vein above a deformed diaphragm. The left atrioventricular connexion was absent. Some points of terminology are considered.