A novel operative technique for postinfarction ventricular septal defect has been used in 44 consecutive patients. The operation consists of excluding rather than excising the infarcted septum and ventricular walls. This is accomplished by performance of a left ventriculotomy through the infarcted muscle and securing a glutaraldehyde-fixed bovine pericardium patch to the endocardium of the left ventricle all around the infarcted myocardium. The ventriculotomy is simply closed over the pericardial patch. There were 21 men and 23 women whose mean age was 69 +/- 7 years. Twenty-nine patients were in cardiogenic shock at the time of operation. All patients had Doppler echocardiography and coronary angiography before operation. All but two patients were operated on during the acute phase of the myocardial infarction. There were six operative deaths. Postoperative complications included renal failure in 10 patients and respiratory failure in 18. Severe right ventricular dysfunction was the only independent predictor of operative mortality. Patients have been followed up for a mean of 40 +/- 34 months. There have been six late deaths and three of these were because of cardiac problems. The actuarial survival at 6 years was 66% +/- 7%. Only one patient had a small residual ventricular septal defect. Late postoperative assessment of ventricular function by echocardiography revealed that most patients had normal or mild impairment of right ventricular function and mild or moderate impairment of left ventricular function. Repair of acute postinfarction ventricular septal defect by endocardial patch with infarct exclusion of the left ventricule probably avoids additional damage to the right ventricle, remodels the acutely infarcted left ventricle, and enhances survival.