Left ventricular dysfunction after acute myocardial infarction: results of a prospective multicenter study

Abstract

In a multicenter prospective study of 866 patients who survived the coronary care unit phase of an acute myocardial infarction, variables reflecting left ventricular function were examined to assess their impact on 2 year survival. Single variables that reflected left ventricular dysfunction before infarction and in the acute and recovery phases were, respectively, history of prior myocardial infarction, rales in the coronary care unit dichotomized at greater than bibasilar and predischarge radionuclide ejection fraction dichotomized at less than 0.40. When combined in a stepwise fashion, patients lacking these three risk characteristics had a 2 year 4.2% mortality rate, whereas patients possessing all three characteristics had a 45% mortality rate. Rales in the coronary care unit and predischarge ejection fraction act independently, and each contributes to mortality. Fifty-two patients with advanced rales but an ejection fraction of 0.40 or greater had a 21% mortality rate. Similarly, 208 patients with few rales but an ejection fraction of less than 0.40 had a 15% mortality rate. These data suggest that the mortality risk imposed by those factors that assess permanent left ventricular damage is independent of and additive to the mortality risk contributed by dynamic, acute phase dysfunction. These data fit the hypothesis that acute phase dysfunction is, in part, due to transient ischemia that, on reversal, can restore function toward normal. The results suggest 1) that assessment of left ventricular function during the acute and recovery phases of myocardial infarction is necessary to define prognostic characteristics of an individual patient, and 2) that of particular importance is the identification of patients whose postinfarction course is consistent with reversible ischemia.