Aneurysms of the posterior interventricular septum with postinfarction ventricular septal defect. Echocardiographic identification.

Using real-time, two-dimensional echocardiographic techniques, we recently studied six consecutive patients with acute myocardial infarction complicated by rupture of the posterior interventricular septum. Each patient experienced an inferior wall myocardial infarction, with a prior anteroseptal infarction in one. In each case, the clinical course was punctuated by the onset of heart failure and a low output state prior to, or coincident with, the appearance of a pansystolic murmur. During two-dimensional echocardiographic study, all six were found to have a discrete aneurysm of the posterior interventricular septum. Septal dyskinesis produced bulging of the interventricular septum far into the right ventricular cavity during systole. Our findings suggest that (1) septal dyskinesis and aneurysm formation may be a valuable sign in diagnosing ventricular septal performation; (2) the reported incidence of postinfarction septal aneurysm at surgery or autopsy may significantly underestimate its true frequency; and (3) septal dyskinesis must by considered as a contributing factor to the compromised hemodynamic status of patients with postinfarction ventricular septal rupture.