ELECTROCARDIOGRAPHIC changes have frequently been reported in cases of acute leukemia,1-6 but they have most commonly occurred as the result of myocardial or pericardial infiltration,1-5,7,8, bleeding into the heart itself,1,4,9 chronic anoxia,10 or infiltration of the conduction tissue6 and valve leaflets.8 Myocardial infarction is rarely mentioned as a concomitant of acute leukemia in large series of such cases. We recently treated a 33-year-old man whose second relapse of acute granulocytic leukemia was complicated by transmural inferolateral myocardial infarction from which he recovered without incident. Report of a Case The patient was a 33-year-old white man who was initially admitted to the Graduate Hospital of the University of Pennsylvania on Sept 10, 1964, because of marked elevation of his white blood cell count (WBC) and cellulitis and deep calf thrombophlebitis of the left leg. Smears of the peripheral blood and aspirated bone marrow were consistent with acute granulocytic leukemia. The cellulitis