Rupture of ventricular septum or papillary muscle complicating myocardial infarction.

Ninety-eight specimens with rupture of some portion of the left ventricle complicating acute myocardial infarction from atherosclerotic coronary disease were studied. In 90, a single structure (so-called isolated rupture) had ruptured as follows: free wall of left ventricle, 52 cases; ventricular septum, 18 cases; a papillary muscle, 20 cases. In eight cases, two structures had ruptured, the most common combination being rupture of ventricular septum and left ventricular wal. Inferolateral location of underlying infarction was the common situation in ruptured papillary muscle, while anteroseptal myocardial infarction was more common in rupture of the ventricular septum. Transmural infarction underlay each case of ruptured ventricular septum, while in ruptured papillary muscle 11 of 20 cases showed subendocardial infarction. There was no association between the type of papillary muscle rupture and the type of infarct. Clinically, collapse of the circulation was common in cases of ruptured ventricular septum and ruptured papillary muscle. Death within one week after rupture was usual when the papillary muscle was involved totally or when the ventricular septum was involved. With partial rupture of a papillary muscle, longer survival (months) was observed in two of ten cases.