study of the association between activity level at onset of symptoms and patient outcome of f irst acute myocardial infarction

this study sought to compare the clinical features and outcome of a first acute myocardial infarction (ami) with onset of symptoms during or within 30 minutes of exercise, at rest and in bed. information collected using a standard questionnaire was used to relate activity at the onset of symptoms and in-hospital outcome in 500 consecutive patients admitted to our heart center with a first ami between 2000-2002. patients with exercise-related onset were more likely to be younger and male. those with onset in bed were more likely to be older and have a history of stable or unstable angina. by way of comparison between patients whose symptoms began at rest and exercise, those with exercise-related onset had lower in-hospital mortality after adjusting for age and gender [odd's ratio (or) 0.53, 95% confidence interval (ci) 0.39-0.93 (p= 0.03)]. compared with patients whose symptoms began at rest, patients with onset in bed had a higher mortality rate [or 1.42,95% ci 1.03 -1.98 (p= 0.028)]. the incidence of moderate or severe left ventricular dysfunction was also lower for exercise -related onset [or 0.79,95% ci 0.6-1.01 (p= 0.32-but not statistically significant)] and higher when onset was in bed [or 1.5, 95% ci 1.2-1.77 (p=0.039)]. there is an association between activity at onset and outcome of ami. differences in pathophysiology or in the population at risk could explain this observation.