IN THE past few years, many strides have been made in the recognition, diagnosis and treatment of congenital lesions of the heart. This case of cardiac diverticulum is presented because of its rarity and to draw attention to the condition. PREVIOUSLY REPORTED CASES Twelve cases have been reported previously, and these are presented in the accompanying table.1 In this series of 12 patients only one survived infancy without surgical intervention, and he died as a result of a rupture of his diverticulum at the age of 4 yr. Few of these cases were discovered at postmortem examinations, and in two the condition was recognized during life and surgical intervention undertaken. The first recorded attempt was that of Wieting (1912), who, on recognizing the condition, replaced the diverticulum into the pericardial sac without considering removal and closed the opening in the diaphragm. Roessler (1944) had a similar case which was