Surgical repair of postinfarction ventricular septal defect. Thirty-one patients underwent repair of postinfarction ventricular septal defect (VSD) from 1980 to 1989. All patients were in New York Heart Association functional class IV, and 15 of them were in cardiogenic shock when operated on. Coronary arteriography was performed in all patients before surgery: nine had one-vessel, 11 had two-vessel, and 11 had three-vessel disease. The VSD was anterior in 15 patients and posterior in 16. The operative technique evolved over the years from a fairly extensive infarctectomy and reconstruction of the septum and right and left ventricular walls with a double Dacron patch, to minimal or no infarctectomy and closure of the VSD by excluding the infarcted muscle from the left ventricular cavity. This is accomplished by suturing a single patch of bovine pericardium to healthy endocardium surrounding the infarcted muscle. The right ventricle is left intact. Overall mortality was 10%, with three operative deaths. All deaths occurred in patients in cardiogenic shock who had three-vessel coronary artery disease. Thus, the mortality for patients in shock was 20%, and the mortality for patients with three-vessel disease was 27%. The operative mortality for patients with posterior VSD was twice as high as in patients with anterior VSD. However, univariate analysis of various clinical, hemodynamic, and operative variables indicated that only three-vessel disease was predictive of operative mortality. Because the number of patients was small and the overall operative mortality relatively low, the results of this analysis may not be valid. 