Atrial Fibrillation in Athletes: Mechanisms, Management, and Future Directions.

BACKGROUND: High-volume endurance training may shift exercise from cardioprotective to arrhythmogenic, increasing the risk of atrial fibrillation (AF) in healthy athletes. CASE SUMMARY: A 38-year-old marathon runner with a 15-year history of high-intensity endurance training presented with episodic palpitations and reduced athletic performance. Electrocardiogram showed paroxysmal AF; echocardiography revealed mild left atrial enlargement without structural heart disease. Symptoms worsened during the recovery phase after runs, suggesting vagally mediated AF. After unsuccessful flecainide therapy, he underwent pulmonary vein isolation. Twelve months later, he remained free of recurrent AF on Holter monitoring and successfully resumed endurance training following an 8-week recovery period. However, ongoing high-volume exercise may still carry a residual risk of arrhythmia. REVIEW SUMMARY: AF in athletes is associated with a 2- to 5-fold increased prevalence linked to atrial remodeling, autonomic imbalance, and inflammation. Rhythm control, especially catheter ablation, preserves performance and quality of life. TAKE-HOME MESSAGE: Excessive endurance training increases AF risk; early rhythm control and structured return-to-play strategies optimize outcomes.