Comparison of P wave indices between ultramarathon athletes and general population

Abstract High‐intensity endurance exercise is linked to increased atrial fibrillation (AF) risk. P wave indices are established AF risk markers, but their role in ultramarathon athletes is unexplored. This study aimed to compare P wave indices between ultramarathon athletes and healthy controls. This cross‐sectional study enrolled 74 ultramarathon athletes and 38 age‐ and sex‐matched healthy volunteers (2:1 ratio). Athletes had completed ≥1 race of ≥100 km or ≥60 km in the past year. Participants with AF, atrial flutter, cardiovascular diseases, or structural heart abnormalities were excluded. Resting 12‐lead ECGs evaluated P wave indices: maximum P wave duration, P wave dispersion, P wave terminal force in lead V1 (PTFV1), and P wave amplitude in lead II (PWAII). The cohort's mean age was 44.8 ± 8.2 years, 70% male. Ultramarathon athletes had significantly higher maximum P wave duration (114.24 ± 7.95 ms vs. 105.76 ± 7.15 ms, p 120 ms) and PTFV1 (≥4000 μV·ms) were significantly more prevalent in ultramarathon athletes (25.7% vs. 5.3%, p = 0.010; 63.5% vs. 5.3%, p < 0.001). Similar findings were observed across genders. Ultramarathon runners demonstrate significant atrial electrical remodeling, as evidenced by abnormal P wave indices, may have potential relevance to arrhythmia risk. Further longitudinal studies are warranted to assess clinical outcomes.