A complication of myocardial infarction usually requiring surgical intervention.

Rupture of the interventricular septum is uncommon (2%), but a very serious complication of an acute myocardial infarction. The septum receives most of its blood supply from the left anterior descending artery and from the posterior descending branch of the right coronary artery. Perforation of the septum occurs in patients with significant disease of both coronary arteries. The prognosis of this complication with medical therapy is poor. There is an 80% mortality rate in the first few days after septal perforation if surgical repair is not attempted. Early diagnosis of ventricular septal rupture complicating an acute myocardial infarction is possible if physical findings are carefully evaluated at frequent intervals. Acute mitral valve pathology and right ventricular infarction can be ruled out by performing right ventricular catheterization to determine intracardiac pressures and oxygen saturations. The echocardiogram is an additional aid in the differential diagnosis.