Pre-Procedural P Wave Duration Is Useful to Estimate Residual Atrial Fibrillation Substrate in Atria after Pulmonary Vein Isolation

Abstract

Background: Prolongation of P wave duration (PWD) is due to conduction delay within atria, and may be used as a pre-procedural predictor of atrial fibrillation (AF) substrate, which could suggest the importance of atrial additional ablation after pulmonary vein isolation (PVI) and higher probability of AF recurrence. Methods: We enrolled 50 patients with paroxysmal AF. Prior to ablation, PWD was obtained using signal-averaged electrocardiogram. To clarify the association between PWD and atrial conduction delay, we measured the conduction time from high right atrium to lateral coronary sinus (HRA-LCS) under the paced rhythm from high right atrium at 100 bpm. After PVI, we assessed remaining AF substrate, defined as AF inducibility by atrial burst stimuli. Results: Prolonged PWD associated significantly with delayed HRA-LCS conduction time (r=0.45, p=0.002). After PVI, AF was induced in 19 (38%) patients. They had longer PWD (143±15 vs. 127±12 ms, p=0.0001), higher left ventricular mass index (132±29 vs. 112±27 g/m2, p=0.028), and larger left atrial volume (85±25 vs. 69±30 cm3, p=0.058) than those without. Multivariate analysis revealed that prolonged PWD was independently associated with AF inducibility (OR=1.1, p=0.005). Conclusion: PWD would predict residual atrial AF substrate after PVI, and may provide pre-procedural information about the efficacy of PVI and the requirement of atrial additional ablation.