B-AB16-03 P WAVE PARADOX: CAN THE P WAVE DURATION ON 12 LEAD ELECTROCARDIOGRAPHY INFORM ATRIAL FIBRILLATION RECURRENCE AFTER CATHETER ABLATION

Atrial depolarization time, as measured on 12 lead electrocardiography (ECG), likely reflects atrial adverse remodeling in patients with atrial fibrillation (AF). It would be anticipated that ablation would decrease P wave duration. Additionally, P wave duration before and after ablation would be expected to associate with AF recurrence. We sought to determine the effect of AF ablation on P wave duration and the association of P wave duration with AF recurrence. A retrospective review identified 739 patients over 5 years who had received AF ablation and had an ECG in sinus rhythm within 1 year prior to the procedure. The P wave duration on ECG was determined pre-procedure and immediately post-procedure by two physicians. The hazard ratio of AF recurrence associated with P wave duration was estimated using the Cox proportional hazard model. Additionally, a direct adjusted survival curve using the Cox model was performed to determine the association of pre-procedure P wave duration with time to AF recurrence. AF ablation is associated with a reduction in mean P wave duration from 92.3 ± 18.7 msec to 85.6 ± 19.9 msec (p < 0.001). Pre-procedure P wave duration greater than 80 msec is associated with lower AF recurrence after ablation (HR 0.67, 95% CI 0.51 - 0.90, p = 0.007). Age, female gender, persistent AF, LA size greater than 5.2 cm, OSA, and pre-procedure P wave duration of 80 msec or less were all independently associated with AF recurrence after ablation. Adjusted survival curves demonstrated that pre-procedure P wave duration of 80 msec or less was independently associated with earlier time to AF recurrence after ablation (Wald test p = 0.01). AF ablation is associated with a significant reduction in mean P wave duration. Shorter pre-procedure P wave duration was associated with earlier time to AF recurrence after ablation. The study suggests that patients with prolonged atrial depolarization likely from atrial adverse remodeling may have a particular advantage from AF ablation that results in the reduction of the P wave duration.