[Hospital mortality of acute myocardial infarct]

Hospital mortality was studied in 541 consecutive patients with acute myocardial infarction (AMI) admitted during a three year period to the Coronary Care Unit (CCU) of the Instituto Nacional de Cardiología de México. Total mortality was 15.3%. Two thirds of the deaths occurred in the CCU. In the remaining fatal cases, the patients had been transferred to regular hospital wards at the time of their death. The largest number of deaths (68.7%) were due to pump failure. A smaller number of patients (14.5%) died as a result of cardiac ruptures. Deaths due to primary arrhythmias have practically disappeared at the CCU's. Hospital mortality due to AMI correlates well with the degree of left ventricular dysfunction. In the cardiogenic shock group and in the acute pulmonary edema group mortality was 93.4 and 50.0% respectively. Patients with moderate degrees of heart failure had a lower mortality rate (18.4%) while in those who did not develop clinical or radiological evidence of left ventricle failure mortality was minimal. In patients with AMI there is a direct relationship between the mass of destroyed myocardium and the degree of left ventricular dysfunction. Thus, mortality is greater in patients with previous infarction, with important enzyme elevation, intraventricular conduction defects, larger cardiac size, etc. Four fifths of the cases studied at post-mortem had a left ventricular mass destruction of at least 40% and most of the cases had significant atheromatous lesions of two or of all three coronary vessels. Further reduction in mortality due to AMI would require an early and effective treatment of the syndromes of left ventricular dysfunction.