Multivariate analysis identified the following factors associated with a greater chance of aspirin use: acute myocardial infarction without Q wave (OR 4.83; 95% CI, 1.02 to 22.77) in relation to any other ECG pattern; beta-blocker use (OR 11.24; 95% CI 3.70 to 34.13) and ACE inhibitor use (OR 4.11; 95% CI 1.89 to 8.94), in relation to the non-use of each one of these drugs. This evidence concerns the gene ACE and acute myocardial infarction.