Histopathology of early myocardial infarcts. A new approach.

The histopathology of human myocardial infarcts is reviewed in a series of 46 cases ranging from sudden death to a clinical age of 3 days. A set of histopathologic features is described whereby the diagnosis of acute myocardial infarction can be made, even in cases of sudden death, on routine sections and even after considerable autolysis. This is primarily a stretching and waviness of the myocardial fibers, especially at the border of the infarcted area. Its mechanism is probably twofold: the rythmical pull exerted by the normal myocardium against the infarcted paralyzed area and the outward bulging of this area at every systole. On the basis of human material alone, it may be inferred that this pattern develops very rapidly: surely less than 1 hour and perhaps a few minutes after the local circulation has failed.