P-wave vector magnitude predicts recurrence of atrial fibrillation after catheter ablation in patients with persistent atrial fibrillation

Background The predictive efficacies of parameters related to P-wave amplitude (PWA) for atrial fibrillation (AF) recurrence after catheter ablation are unclear. Methods We measured multiple PWA parameters using an automated system in 126 consecutive patients with persistent and long-standing persistent AF who underwent catheter ablation. The relationships between AF recurrence and various PWA parameters were examined, including the association with P-wave vector magnitude (calculated as the square root of the sum of lead II PWA squared, lead V6 PWA squared, and a one-half lead V2 PWA squared). Results Atrial fibrillation did not recur in 87 patients (69%) during 32 +/- 15 months of follow-up. The maximum PWA, mean PWA, and P-wave vector magnitude were lower in patients with AF recurrence than those without (maximum PWA, 0.14 +/- 0.05 mV vs. 0.16 +/- 0.05 mV, p = 0.017; mean PWA, 0.05 +/- 0.02 mV vs. 0.06 +/- 0.02 mV, p = 0.003; P-wave vector magnitude, 0.09 +/- 0.03 mV vs. 0.13 +/- 0.04 mV, p < 0.001). A multivariate Cox regression analysis revealed that the predictive ability of P-wave vector magnitude for AF recurrence was independent of other clinical properties (hazard ratio: 0.153, 95% confidence interval: 0.046-0.507, p = 0.002). Atrial fibrillation freedom rates of patients with P-wave vector magnitude higher and lower than 0.13 mV were 93% and 57%, respectively. P-wave vector magnitude weakly correlated with left atrial dimension (R = -0.280, p = 0.004). Conclusions P-wave vector magnitude can predict AF recurrence after catheter ablation in patients with persistent AF.