Purpose: The development of left ventricular systolic dysfunction or heart failure following an acute myocardial infarction (MI) is a powerful marker of an adverse prognosis. Recurrent MI could be an important cause of death, either directly or by provoking arrhythmias.
Methods: The OPTIMAAL trial randomized 5477 patients with heart failure or evidence of left ventricular dysfunction following acute MI to losartan or captopril. Over a follow-up of 2.7 years, there were 946 deaths. Of the 180 (19%) of these deaths for which autopsy reports were available, acute MI was found in 57% (102 of 180) of the autopsies. By comparison, an endpoints adjudication committee using clinical data attributed death to acute MI in only 29 cases. An acute MI was found at autopsy in 55% (37 of 67) of the deaths that had been classified as due to an arrhythmia and in 81% (21 of 26) of the deaths classified as due to progressive heart failure. Including autopsy diagnoses, the rate of acute MI in patients who died suddenly was independent of the time elapsed since the index MI, but in patients not classified as dying suddenly, there was a time-related decrease in recurrent MI from 78% in the first 30 days to 30% by the end of follow-up. However, only 19% of patients who died underwent autopsy, so recurrent MI may have been substantially more common and perhaps had a different relation to time since the index MI if more patients had undergone autopsy.
Conclusions: In patients with evidence of major cardiac dysfunction after MI, recurrent MI found at autopsy is common and has often not been clinically detected.