CLINICOPATHOLOGICAL STUDY OF THE ROLE OF INFARCT EXPANSION IN PATIENTS WITH CARDIAC RUPTURE FOLLOWING ACUTE MYOCARDIAL-INFARCTION

The purpose of this study was to clarify whether the infarct expansion with cardiac rupture following acute myocardial infarction pathomorphologically differed from expansion without rupture. Eighteen autopsied patients with rupture were classified into acute phase (time between the onset of myocardial infarction and death less than or equal to 36 h) and subacute phase (> 36 h). These patients were compared with 25 patients with no rupture using new parameters of expansion: radius index, cavity index, expansion area index and thinning-dilatation index of the left ventricle. In the acute phase, each parameter was significantly higher in the ruptured group than in the non-ruptured group (radius index: 0.49 +/- 0.28 vs 0.14 +/- 0.16, p < 0.005, cavity index: 0.21 +/- 0.09 vs 0.08 +/- 0.06, p < 0.005, expansion area index: 0.75 +/- 0.25 vs 0.34 +/- 0.23, p < 0.001, thinning-dilatation index: 2.89 +/- 1.31 vs 1.53 +/- 0.52, p < 0.001). However, in the subacute phase there were no differences in these parameters between the two groups. These data suggest that in the acute phase, but not the subacute phase, the degree of expansion and the proportion of expansion to infarcted area are associated with rupture.