Atrial fibrillation among master athletes: A complex relationship

Background: Atrial fibrillation (AF) is the most common sustained arrhythmia with a notable impact on morbidity and mortality. While moderate physical activity is generally protective against cardiovascular disease, the relationship between endurance sports and AF, especially in master athletes (aged ≥45), remains unclear. Some evidence suggests a U-shaped association between exercise intensity and AF risk. Objective: To investigate the association between endurance sport participation and AF occurrence among master athletes, and to identify potential risk factors or predisposing conditions. Methods: This observational case-control study enrolled 140 endurance athletes aged ≥45 years, divided into 70 with documented AF (cases) and 70 age- and activity-matched athletes without AF (controls). Data collected included demographic, anthropometric, sports participation, cardiovascular and extracardiac comorbidities, 24-h Holter ECG and echocardiographic parameters. Statistical comparisons were performed to identify differences between groups. Results: Groups were comparable in age, sex and BMI. Both groups had similar patterns of endurance sport participation. Athletes with AF had a significantly higher burden of cardiovascular risk factors, notably hypertension (73% vs. 21%) and dyslipidaemia (54% vs. 14%), and more extracardiac comorbidities. Echocardiography revealed larger left atrial size and more frequent mitral and tricuspid regurgitation in the AF group. Most AF cases were paroxysmal, with palpitations reported in over 80%. Conclusions: The main findings of our study suggest that endurance athletes experiencing AF show a higher prevalence of traditional cardiovascular risk factors, particularly hypertension and dyslipidaemia. These findings highlight the need for individualized cardiovascular assessment and risk management in this population. Further longitudinal studies are needed to clarify the causal role of sustained high-intensity exercise in the development of AF.