The first few years that a new procedure or technique is used for treating a disease constitute an exploratory period. As experience accumulates the criteria for the selection of patients are modified, techniques are refined and standardized, and possible errors and problems in surgical management are more clearly recognized, with the result that both morbidity and mortality decrease. Sufficient time has passed now and enough experience has been gained to evaluate some of the factors which are important in determining the outcome of cardiac procedures. This paper is an analysis of the surgical treatment of 231 patients with atrial and ventricular septal defects operated upon before July 1, 1959, and is an attempt to point out the factors influencing the mortality and morbidity and the results in this group of patients.
The total number of cases has been divided into the groups shown in Figure 1. Their age range and