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 pathomorph ologically 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 p atients with no rupture using new parameters of expansion: radius inde x, cavity index, expansion area index and thinning-dilatation index of the left ventricle. In the acute phase, each parameter was significan tly higher in the ruptured group than in the non-ruptured group (radiu s 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 ther e were no differences in these parameters between the two groups. Thes e data suggest that in the acute phase, but not the subacute phase, th e degree of expansion and the proportion of expansion to infarcted are a are associated with rupture.