COR TRIATRIATUM - PATHOLOGIC ANATOMY AND A CONSIDERATION OF MORPHOGENESIS BASED ON 13 POSTMORTEM CASES AND A STUDY OF NORMAL DEVELOPMENT OF PULMONARY VEIN AND ATRIAL SEPTUM IN 83 HUMAN EMBRYOS

The principal pathologic findings in 13 cases of classical cor triatriatum were presented, including the first documented case of complete transposition of the great arteries and the fourth reported case of tetralogy of Fallot with cor triatriatum. Findings relevant to this anomaly were reported from a study of normal development of the pulmonary vein and atrial septum, based on 83 human embryos. Attention was focused on the origin, course, and incorporation of the common pulmonary vein and on the origins and development of septum primum, the left venous valve, and the intersepto-valvular space. The pathologic and embryologic findings strongly suggest that cor triatriatum results from entrapment of the left atrial ostium of the common pulmonary vein by tissue of the right horn of the sinus venosus from which septum primum develops, leading to failure of incorporation of the common pulmonary vein into the left atrium during the fifth embryonic week. © 1969.