The Relation between the Location of Coronary Occlusions and the Occurrence of Shock in Acute Myocardial Infarction

Abstract

Postmortem and clinical data for 127 patients dying of acute myocardial infarction were correlated to determine the relationship between primary branch occlusions and cardiogenic shock. The relative frequency of shock was significantly greater in patients with branch occlusions than in those with main stem occlusions or infarction without fresh occlusion. Branch occlusions in the distribution of the left circumflex coronary artery had a particularly high association with shock. Patients with and without shock were not significantly different with respect to the size of the infarct and the extent of coronary atherosclerosis. Most of the patients with shock and branch occlusions had large infarcts and extensive coronary atherosclerosis. A reflex mechanism, with receptor sites in the primary branches of the coronary arteries, may be implicated in the pathogenesis of shock in certain cases of acute myocardial infarction, as has been demonstrated in the experimental animal. Shock also occurs in patients with myocardial infarction who have had main stem occlusion, or no occlusion at all. Further studies of reflex factors in shock associated with myocardial infarction are suggested. A clearer understanding of these factors may have important therapeutic implications.