ASSOCIATION BETWEEN ACTIVITY AT ONSET OF SYMPTOMS AND OUTCOME OF ACUTE MYOCARDIAL-INFARCTION

Objectives. This study sought to compare the clinical features and out come of a first myocardial infarction with onset of symptoms during or within 30 min of exercise, at rest and in bed, Background It is not k nown whether activity at onset influences outcome of acute myocardial infarction. Methods. Information collected using a standard questionna ire was used to relate activity at the onset of symptoms to in hospita l outcome in 2,468 consecutive patients admitted to a coronary care un it with a first myocardial infarction between 1975 and 1993. Results. Patients with exercise-related onset were more likely to be younger an d male. Those with onset in bed were more likely to be older and have a history of stable or unstable angina. Compared with patients whose s ymptoms began at rest, those with exercise related onset had a lower i n-hospital mortality rate after adjusting for age, gender and year of admission (odds ratio [OR] 0.60, 95% confidence interval [CI] 0.40 to 0.89), and patients with onset in bed had a higher mortality rate (OR 1.38, 95% CI 1.03 to 1.85), The incidence of cardiac failure requiring diuretic therapy was also lower for exercise related onset (OR 0.83, 95% CI 0.67 to 1.04) and higher when onset was in bed (OR 1.36, 95% CI 1.11 to 1.66). Conclusions. There is an association between activity at onset and outcome of acute myocardial infarction, Differences in pa thophysiology or in the population at risk could explain this observat ion. (C) 1997 by the American College of Cardiology.