Prognostic Significance of QRS Duration in Patients With Suspected Coronary Artery Disease Referred for Noninvasive Evaluation of Myocardial Ischemia
The purpose of this study was to evaluate the prognostic significance of QRS duration in patients with suspected coronary artery disease (CAD) referred for noninvasive evaluation of myocardial ischemia by dobutamine stress echocardiography. QRS duration is a prognostic marker in patients with previous myocardial infarction and/or heart failure. The relation between QRS duration and outcome of patients without known heart disease has not been evaluated. A total of 1,227 patients (707 men, mean age 61 ± 14 years) with suspected CAD underwent dobutamine stress echocardiography for evaluation of myocardial ischemia. Patients were followed to determine predictors of cardiac events and to assess the incremental significance of QRS duration compared to clinical and dobutamine stress echocardiographic data. During a mean follow-up of 4.2 ± 2.4 years, 280 patients (23%) died (129 cardiac deaths), and 60 (5%) had a nonfatal infarction. Annualized cardiac death rates were 2.0% in patients with QRS duration <120 ms and 4.4% in patients with QRS duration ≥120 ms, respectively (p <0.0001). Annualized event rates for cardiac death/nonfatal infarction were 2.8% in patients with QRS duration <120 ms and 4.8% in patients with QRS duration ≥120 ms (p = 0.0001). Multivariate models identified age, male gender, smoking, QRS duration ≥120 ms, and an abnormal dobutamine stress echocardiogram as independent predictors of cardiac death and the combined end point cardiac death/nonfatal infarction. In conclusion, QRS duration is an independent predictor of cardiac death and cardiac death/nonfatal infarction in patients with suspected CAD. This risk is persistent after adjustment for clinical variables, left ventricular function, and myocardial ischemia.