Frequent atrial premature complexes during exercise: A potent predictor of atrial fibrillation

Abstract

Background: The clinical significance of atrial premature complexes (APCs) during exercise is unclear. Hypothesis: Frequent APCs during exercise provides prognostic information. Methods: A total of 998 patients were divided into 2 groups based on the presence of frequent APCs during treadmill testing (>5 beats per stage): the FAPC group (n = 128) vs the non-FAPC group (n = 870). The primary outcome was new-onset atrial fibrillation or flutter (AF/AFL) during follow-up period (356.2 ± 131.1 days). Results: Mean age was 56.0 ± 10.2 years in the FAPC group and 52.6 ± 12.0 years in the non-FAPC group (P = 0.001). Baseline electrocardiographic and echocardiographic findings were not significantly different between the 2 groups. During exercise, maximal heart rate did not differ between the 2 groups. Chronotropic incompetence was more prevalent in the FAPC group than in the non-FAPC group (P = 0.04). During follow-up, the FAPC group had a higher incidence of AF/AFL than did the non-FAPC group (7 patients [5.5%] vs 5 patients [0.6%]; P < 0.001). Treadmill-induced frequent APCs (adjusted hazard ratio [HR]: 15.23, 95% confidence interval: 4.59-50.56, P < 0.001), chronotropic incompetence (adjusted HR: 19.95, 95% CI: 6.02-66.10, P < 0.001), and palpitation as a reason for treadmill testing (adjusted HR: 5.72, 95% CI: 1.64-20.00, P = 0.01) were independent risk factors that predicted new-onset AF/AFL. Conclusions: Frequent APCs during treadmill testing was associated with development of AF/AFL in this study. Close monitoring for further AF/AFL development is needed in these patients.