Does the electrocardiographic presence of Q waves influence the survival of patients with acute myocardial infarction?

AIMS: To compare the outcome of short- and long-term survival of patients with Q wave vs non-Q wave myocardial infarction. METHODS: A total of 6676 patients with acute myocardial infarction were enrolled on the TRAndolapril Cardiac Evaluation (TRACE) register between 1990 and 1992. Medical history, electrocardiographic diagnosis of Q wave and non-Q wave myocardial infarction, echocardiographic estimation of left ventricular systolic function determined as wall motion index, infarct complications, and survival were documented. The factors influencing the postmyocardial infarction outcome of these patients were studied after 30 days and after 8 years of follow-up, respectively. RESULTS: Cox proportional-hazard models demonstrated that the electrocardiographic Q waves had significant influence on survival during the first 30 days [risk ratio 1.4 (95% confidence limits 1.2-1.7)] but no influence thereafter [1.0 (0.9-1.1)]. The result was the same in univariate and multivariate analyses. Subgroup analysis defined by age, sex, wall motion index, presence of congestive heart failure, diabetes mellitus, arterial hypertension, subsequent myocardial infarctions and use of thrombolytic therapy did not disclose importance of Q waves on mortality. CONCLUSION: The electrocardiographic presence of Q waves is associated with increased mortality during the initial 30 days after a myocardial infarction, but has no influence thereafter.