Shock after acute myocardial infarction. A clinical and hemodynamic profile

Clinical features, predisposing factors, precipitating events, laboratory and hemodynamic observations, pathologic findings, prognostic indicators and the results of therapy are surveyed for 73 patients in whom shock developed after acute myocardial infarction. The incidence of shock was 15 percent, and the mortality 86 percent. It was not possible to differentiate patients with shock from those with acute infarction alone on the basis of age, anamnestic data, delay before hospitalization or anatomic location of infarction. No precipitating cause for shock other than acute infarction itself was consistently present. Hypovolemia, anemia, arrhythmia and drugs could not be incriminated as important factors in the genesis of shock. Extensive myocardial damage, coronary atherosclerosis and left ventricular hypertrophy were found at postmortem examination in most patients who died, but similar findings were noted in a group of patients in the coronary care unit who died without evidence of shock during the period of the study. Delay in onset of shock in many cases suggested progression of cardiac damage after the initial clinical event. Hemodynamic studies in 19 patients showed that cardiac index was less than half of the normal index, stroke volume index about a third of normal, and peripheral resistance generally increased. We conclude that patients who have the highest risk can be identified from various clinical and hemodynamic observations. It is appropriate to consider such patients for unconventional therapy.