Thirty-eight patients have been operated upon early after acute myocardial infarction with rupture of the ventricular septum. Preoperative management included bedside hemodynamic evaluation, mechanical left heart support, and pharmacologic agents. The results of the surgical repair reflected both the effectiveness and the duration of preoperative treatment. Operation was performed in 14 patients with refractory cardiogenic shock, 10 of whom died (71%). Hemodynamic and clinical stability was achieved in 24 patients. Early operation (average 46 hours of medical management) in 17 patients permitted accurate repair, even with friable tissues; four of these patients died (23%). Delayed operation (average 12 days of monoperative treatment) was performed in seven patients and resulted in a higher mortality rate, three patients dying (43%). The location of the ventricular septal defect (VSD) also influenced the operative risks, the prognosis for posterior defects being worse than that for anterior defects. Optimal myocardial preservation during the entire procedure is of crucial importance to the success of the operation.