Classification of cardiac rupture complicated in myocardial infarction. Pathological study of 32 cases.

Thirty of 32 cases with cardiac rupture (CR) complications in the myocardial infarction were found out of a total of 91 cases of acute myocardial infarction (AMI). The mean age of the ruptured group in females was significantly younger than that of the non-ruptured group. Twenty-one cases showed free wall rupture of the left ventricle, six perforation of ventricular septum and three double rupture. All cardiac ruptures occurred in cases of transmural infarction. The age of AMI was histologically estimated. Nine cases complicated within the first 24 hours of AMI showed rupture of the left anterior wall. CR in the periphery within the infarct occurred at any time during the first week after onset, and cases of the central rupture were increased in number after the 3rd day of AMI. Pathologic findings indicated that elevated wall tension was considered to be most closely related to the cause of CR. Thirty two cases of CR were classified into three types: (1) blowout type, (2) hemorrhagic dissecting type, and (3) thinning-with-rupture type. Hemorrhagic dissecting type was characterized by multiple endocardial ulcers and fissure canals extending from the ulcer with hemorrhage in the surrounding myocardium. Complex fissure was seen in two cases of this type.