Afterload reduction in the management of postinfarction ventricular septal defect

The primary goal in the medical management of ventricular septal defect complicating myocardial infarction is to support cardiac function and control symptoms, if possible, for a period of 4 to 6 weeks. If the patient survives this period, surgical correction of the defect is technically easier and safer. In many cases, however, cardiac function is severely compromised, intractable biventricular failure develops, early operation is necessary and the likelihood of successful repair is diminished.

We recently treated two such patients by means of afterload reduction with nitroprusside. In one patient, sublingually administered isosorbide dinitrate was later used, and prolonged survival was achieved after surgery. Hemodynamic investigations in both cases demonstrated that nitroprusside improved cardiac output without necessarily decreasing mean arterial pressure. The effect of nitroprusside on pulmonary blood flow and left to right shunt was variable: One patient demonstrated a decrease in the ratio of pulmonary to systemic blood flow, and the other did not. We conclude that afterload reduction with either intravenous or oral agents is a potentially useful measure in the management of patients with ventricular septal defect complicating myocardial infarction.