Association of eosinophils with cardiac rupture.

Cardiac rupture occurs in 10 per cent of patients who die with acute myocardial infarction, but the pathogenesis remains unclear. Twenty randomly selected patients with cardiac rupture were reviewed retrospectively at autopsy, and the findings were compared with those of 20 age- and sex-matched control subjects who had died of acute transmural myocardial infarction without rupture. The times from the onset of chest pain to death were similar in the two groups (5.7 +/- 5.8 days for patients with rupture versus 4.2 +/- 4.9 days for control subjects), and there were no differences in the incidences of systemic hypertension, diabetes mellitus, hypercholesterolemia, history of myocardial infarction, or angina pectoris. The severity of coronary atherosclerosis was different in the two groups, with 55 per cent of the patients with cardiac rupture having single-vessel disease and 70 per cent of the patients without cardiac rupture having disease in three vessels. Additionally, the incidence of thrombosis was greater in patients with cardiac rupture than in those without. The inflammatory cell response in each patient was quantitated microscopically (number and type of leukocytes) in ten high-power fields. The inflammatory response was greater in patients with cardiac rupture. The number of eosinophils in the inflammatory response was significantly (P less than 0.01) greater in hearts associated with cardiac rupture (29.5 +/- 4 per cent) than in control hearts (11.7 +/- 3.1 per cent). It is postulated that eosinophils rich in arylsulfatase B, peroxidase, glucuronidase, beta-glycerophosphatase, major basic protein, and eosinophilic cationic protein may further weaken the necrotic myocardium and, in part, determine whether acute myocardial infarction will eventually result in cardiac rupture.