Acute Myocardial Infarction Not Due to Coronary Artery Occlusion

It is well known that the clinical and electrocardiographic features of coronary thrombosis may be observed in patients in whom a coronary artery thrombus is subsequently not found at necropsy. In such patients the clinical picture may have been caused by a myocardial infarct in the absence of a coronary artery occlusion. The occurrence of recent myocardial infarction without acute coronary thrombosis has been noted by Libman,1Oberndorfer,2Büchner,3Hamburger and Saphir,4Dietrich,5Levy and Bruenn6and others.7We have therefore undertaken a detailed systematic study of the myocardium and of the coronary vessels in order to determine the relative frequency of myocardial infarction without coronary occlusion and to discover, if possible, what physiologic factors and what clinical conditions are responsible. It is theoretically conceivable that myocardial infarction may occur whenever there is severe myocardial ischemia, even in the absence of a mechanical