Prior to the development of intracardiac surgery the group of congenital anomalies associated with persistence of the ostium primum, although known to pathologists, was not clearly separated from other types of septal defect in the minds of clinicians. However, their physiologic and surgical implications are of great importance.1,2 Bailey et al. have reported postoperative death in 11 of 16 patients with the ostium primum type of atrial septal defect but in only 3 of 30 with other types, such as ostium secundum. The purposes of this paper are to review the descriptive literature, to suggest a possible relationship and a scheme of classification of these various entities, to emphasize a reason for the high operative mortality, and to point out clinical features of diagnostic significance.
Persistent common atrioventricular canal is probably the most familiar complex associated with ostium primum. There are four features.First, there is a defect