A Three-Year Study of Myocardial Infarction in a Large Employed Population

During a three-year period, 653 employees had an initial acute myocardial infarction. The incidence rate was much greater in men than in women, but the difference between the sexes decreased with increasing age. Executive personnel had the lowest incidence rate, while the highest rate was found in lower level salaried employees. The chances of developing an attack were about the same at work, at home, away on vacation, or at other places. Only 5.4 per cent of the patients were indulging in unusual physical exertion at the time of the attack. The case fatality rate was 31.4 per cent. The probability of survival was adversely affected by increasing age and, among older persons, by hypertension. The electrocardiograms of about 77 per cent of the patients were normal prior to the attack, but several kinds of abnormalities that were present were more common in the patients than in matched controls.