Coronary Spasm as a Primary Cause of Myocardial Infarction

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Abstract
An hypothesis is presented which contends that localized temporary coronary arterial spasm, plus coronary sclerosis, is the usual cause of myocardial infarction. Coronary thrombosis, if it occurs at all, is believed to be secondary to stagnation of the blood in the coronary artery and is rarely, if ever, the primary cause of the infarct. Dog experiments, human autopsy, and arterio-graphic evidence, epidemiological studies, and consideration of the prodromal symptoms prior to myocardial infarction lend support to this hypothesis. A case is presented which was treated with nitrates during what might otherwise have been the prodromal stage of a myocardial infarction, and no infarction occurred. It does not seem reasonable to assume that a thrombus was developing in the constricted portion of a coronary artery during the entire period of the prodromal symptoms in many instances. A more rational explanation would be sclerosis plus spasm causing progressive myocardial inchemia during the prodromal period, perhaps with complete occlusion of the artery by thrombus occurring at the time that the clinical picture becomes desperate. A series of 100 patients was observed for 466 patient months without, and 709 patient months with possible protection from the pedicle operation. There were 2 nonfatal infarcts in the former group sufficiently severe to change the QRS complex after a maximal interval of 3 months, and there were none in the second group. The difference between these 2 groups is not significant but the total number of infarcts in each is believed to be far less than would be expected in a comparable series of patients with other types of medical management, and is presumably related to the drug management that was used.