Pathogenesis of Cardiac Rupture Due to Myocardial Infarction

1.A clinical and pathological study was made of 26 cases of myocardial infarction with rupture.2.Their average age was 70.5 years. There were 16 males and 10 females. There was no previous history of infarction in any case. Based upon histological study, the age of the infarct at the time of rupture was less than two weeks in all, less than one week in 19, and less than three days in ten.3.Etiological factors such as hypertension, over-exertion, fatty infiltration and granulocytic exudation were not found to be of particular significance in this series.4.A factor considered in our series to be important in the cause of cardiac rupture in myocardial infarctions was penetration of the wall by a dissecting hematoma. Such a hematoma was found in a majority of cases. In a substantial number blood penetrated the wall by infiltration in the loose interstitial tissue between intact myocardial fibers. In a few the hematoma penetrated mainly through necrotic myocardial fibers. An analogy is drawn between the mechanism of this dissecting hematoma and that found in dissecting aortic aneurysm.