[Cardiac rupture: histological study of ruptured and non-ruptured myocardial infarcts (author's transl)].

178 myocardial infarcts with wall rupture and 116 without were studied histologically. Mean morphological age of the infarct was 3.7 in the ruptured and 2.9 days in the non-ruptured cases. 57.7% of patients had died within the first 24 hours from a non-ruptured infarct. Death rate within the first 24 hours after infarction was 57.7% among the non-ruptured cases, 25.8% among those with rupture. 23.1% of infarcts had ruptured between the third and fourth day. Only 5.1% of patients with non-ruptured infarcts had died on the third or fourth day. Transmural infarction was present in 71.7% of those that had ruptured. The ruptured channel in general ran through the middle of the necrotic-infarcted, leucocyte-infiltrated myocardium. Infarct recurrence was demonstrated in 20% of ruptured and 73% of non-ruptured infarcts. Morphological comparison indicated that transmural infarction and marked leucocytic reaction in a not previously infarct-damaged myocardium are the main causes for rupture in myocardial infarction.