Clinical and Cardiovascular Magnetic Resonance Characteristics of Veteran Male Endurance Athletes With Atrial Fibrillation: VENTOUX‐AF

Background Older male endurance athletes exhibit an increased risk of atrial fibrillation (AF) of which the pathogenesis is unclear. We aimed to determine whether left atrial (LA) remodeling on cardiovascular magnetic resonance, blood pressure during exercise, and bradyarrhythmia on implantable loop recorder monitoring were associated with AF in athletes. Methods VENTOUX‐AF (Cardiac Magnetic Resonance Assessment of Left Atrial Fibrosis in Veteran Endurance Athletes) was a cross‐sectional study comparing 39 male athletes with AF (27 symptomatic and 12 detected on implantable loop recorder) aged ≥50 years exercising ≥10 hour/week for ≥15 years with 94 exercise‐matched male athletes in sinus rhythm and 33 sedentary male patients with AF. Participants underwent exercise testing and 3‐dimensional late‐gadolinium enhancement cardiovascular magnetic resonance with LA fibrosis quantification. A total of 106 asymptomatic athletes in sinus rhythm at recruitment received implantable loop recorder to detect incident AF and bradyarrhythmia. Results Exercise systolic (208.5±29.9 versus 192.4±25.9 mm Hg, P=0.008) and exercise diastolic blood pressure (96.4±17.6 versus 88.3±9.7 mm Hg, P=0.02) were greater in athletes with AF than athletes in sinus rhythm. There was no difference in LA remodeling indices including LA fibrosis between these groups. During follow‐up (median 730 days) of 106 athletes in sinus rhythm at baseline with implantable loop recorder, AF cumulative prevalence was 11.3% (12/106) and significantly associated with bradyarrhythmia (hazard ratio 5.89, 95% CI, 1.59–21.8, P=0.008). LA ejection fraction (52.5±11.6 versus 39.1±17.3%, P<0.001), LA fibrosis (7.6 [interquartile range, 4.7–9.2]) versus 2.9% [1.8–5.6], P=0.02) and exercise systolic blood pressure (208.5±29.9 versus 183.2±30.8 mm Hg, P<0.001) were greater in athletes with AF than sedentary patients with AF. Conclusions Hypertensive response to exercise was common in athletes with AF but LA remodeling and fibrosis were not. Further studies are required to determine whether these factors play a role in the pathogenesis of AF in athletes.