[Pathological patterns of reperfused myocardial infarction. Experimental study (author's transl)].

The effect of the reperfusion on the pathological appearance of experimental myocardial infarction has been studied in the rat (87 animals). Following permanent ischemia (33 animals sacrified after 1, 6, 24 and 48 hours), there appeared a reproducible extended transversal infarction marked by an uniform sequence of histologic, histoenzymatic and ultrastructural changes. Following temporary ischemia (54 animals), the pathological patterns were marked by myofibrillar degeneration (contraction band necrosis), cellular edema, calcium deposits and interstitial hemorrhages. These changes appeared after reperfusion of short duration (10 minutes). Sarcolemmal and capillary permeability alterations could be the main factor involved in the reperfusion injury. Similar tissue damage have been found in clinical conditions in subendocardial hemorrhagic necrosis after cardiopulmonary by-pass, and in reperfused infarction.