Temporal Association Between Exercise and Arrhythmia Episodes in Endurance Athletes With Paroxysmal Atrial Fibrillation

BACKGROUND: Atrial fibrillation (AF) is a prevalent arrhythmia in endurance athletes, and many athletes report exercise as a trigger for AF episodes. We aimed to investigate the association between exercise sessions and arrhythmia episodes in endurance athletes with paroxysmal AF. METHODS: In endurance athletes diagnosed with paroxysmal AF, we continuously monitored arrhythmia episodes using insertable cardiac monitors and report event rates per 24 hours and temporal relation of arrhythmias with exercise sessions. Sports watches and chest straps were used for exercise monitoring. Exercise with a heart rate of 76% to 84% and ≥ 85% of the individual maximum heart rate was classified as high and very high intensity, respectively. RESULTS: Forty-seven athletes (age 57±10, range 33-75 years, 3 women) were monitored with insertable cardiac monitors for a total of 55 994 hours (median 1008 [840-1344] equaling 42 days [35-56]) and performed a total of 1722 hours of exercise, of which 592 hours at high or very high intensity. Thirty-one athletes (66%) had a total of 1445 (median 17 [3-33]) AF episodes during monitoring. Thirteen athletes (27%) had AF during exercise of whom 2 had AF during high-intensity sessions. The event rate of AF was not higher during (0.34 per 24 hours [95% CI, 0.13-0.65]) or subsequently following an exercise session (0.37 [95% CI, 0.10-0.71]), compared with unrelated to exercise (>3 hours after, 0.61 [95% CI, 0.26-1.13]). There were no episodes of exercise-related ventricular tachycardia. CONCLUSIONS: In this study on endurance athletes with paroxysmal AF, the rate of AF episodes was not increased during or subsequently following exercise sessions. REGISTRATION: URL: Study Details: NCT04991337. Effects of Detraining in Endurance Athletes With Atrial Fibrillation. ClinicalTrials.gov (NEXAF Detraining).