Phenotypic Analysis of P-Wave Morphology as a Key Determinant of Late Recurrence Post-Ablation in Paroxysmal Atrial Fibrillation.

Background: It remains unclear how P-wave morphology characteristics can be used to stratify the risk of late recurrence after catheter ablation (CA) for atrial fibrillation (AF). Methods: Patients with paroxysmal AF who underwent an initial CA were enrolled. We investigated the association between P-wave morphology (P-wave duration (Pd), PQ interval, P-wave amplitude (PWA) in leads II, V2, and V6) and late arrhythmia recurrence. Patients were classified into groups using statistical methods, and differences in recurrence and predictive scores for low voltage areas (LVA) among the groups were evaluated. Results: A total of 1005 paroxysmal AF patients undergoing initial CA were included. Cox regression identified female sex, Pd > 124 ms, PQ > 196 ms, and low PWA in leads II, V2, and V6 as predictors of late recurrence. Hierarchical clustering defined three phenotypes: Phenotype 1 (isolated low PWA), Phenotype 2 (isolated prolonged Pd) and Phenotype 3 (low PWA with prolonged Pd). At 1-year, cumulative recurrence rates were 10.1% (95% CI 0.8-15.7), 7.0% (4.7-9.6), and 36.2% (30.8-42.3) for Phenotypes 1-3; at 3-year, rates were 17.4% (12.8-23.3), 10.2% (7.4-14.0), and 61.2% (54.8-67.6). Phenotype 3 showed the highest risk, with HRs of 4.84 (95% CI 3.42-6.84) versus Phenotype 1 and 7.44 (4.34-12.8) versus Phenotype 2 (both Conclusions: Low PWA across multiple leads (II, V2, and V6), especially when combined with prolonged Pd, correlates with late arrhythmia recurrence and suggests the potential presence of LVA.