Fifty-five patients had surgical repair of postinfarction ventricular septal rupture in Massachusetts General Hospital from 1968 through 1981. In patients operated more than three weeks after infarction, hospital survival has been 93% (14/15). Before 1975 in patients operated less than three weeks after infarction, hospital survival was 41% (7/17). In this same era patents operated for septal rupture with cardiogenic shock present before operation had a hospital survival rate of only 27% (3/11). Before 1975 patients with cardiogenic shock were supported with intra-aortic balloon pumping (IABP) and vasopressors, and operation deferred pending hemodynamic stabilization. Before 1975 patients with anterior septal rupture had a hospital survival rate of 64% (9/14), while patients with posterior septal rupture had a hospital survival rate of only 38% (5/13). This difference in survival according to the location of septal rupture occurred despite comparable numbers of patients in each group requiring early operation, as well as incidence of cardiogenic shock. Since January 1, 1975 patients operated less than three weeks after infarction have had an overall hospital survival rate of 70% (16/23). Of the 10 most recent patients operated early, nine are survivors. In patients with anterior defects 85% (11/13) survived, while in patients with posterior defects 67% survived (10/15). In patients operated with cardiogenic shock present before operation, survival has been 67% (10/15). Changes in management leading to improved results include (1) immediate operation for patients with cardiogenic shock, (2) cold cardioplegic protection of the myocardium, and (3) prosthetic replacement of posterior left ventricular free wall defect, after infarctectomy and septal repair, in patients with posterior septal rupture.