Effect of Atrial Fibrillation on Outcome in Patients With Known or Suspected Coronary Artery Disease Referred for Exercise Stress Testing

The association of atrial fibrillation (AF) with coronary artery disease (CAD) remains controversial. In addition, the relation of AF to myocardial ischemia and outcomes in patients with known or suspected CAD referred for exercise stress testing has been poorly explored. In this study, 17,100 patients aged ≥50 years with known or suspected CAD who underwent exercise electrocardiography (n = 11,911) or exercise echocardiography (n = 5,189) were evaluated. End points were all-cause mortality, nonfatal myocardial infarction, and coronary revascularization. Overall, 619 patients presented with AF at the time of the tests. Patients with AF who had interpretable electrocardiograms had a lower likelihood of exercise-induced ischemic ST-segment abnormalities (adjusted odds ratio 0.51, 95% confidence interval 0.34 to 0.76, p = 0.001), and those with AF who underwent exercise echocardiography had a lower likelihood of new or worsening exercise-induced wall motion abnormalities (adjusted odds ratio 0.62, 95% confidence interval 0.44 to 0.87, p = 0.006). During a mean follow-up period of 6.5 ± 3.9 years, 2,364 patients died, 1,311 had nonfatal myocardial infarctions, 1,615 underwent percutaneous coronary intervention, and 922 underwent coronary artery bypass surgery. The 10-year mortality rate was 43% in patients with AF compared to 19% in those without AF (p <0.001). In multivariate analysis, AF remained an independent predictor of all-cause mortality (adjusted hazard ratio 1.45, 95% confidence interval 1.20 to 1.76, p <0.001), but not of nonfatal myocardial infarction or coronary revascularization. In conclusion, despite being associated with an apparently lower likelihood of myocardial ischemia, AF was an independent predictor of all-cause mortality in patients with known or suspected CAD referred for exercise stress testing.