RESUMO
INTRODUCTION: Paroxysmal atrial fibrillation (PAF) frequently occurs in patients with Wolff-Parkinson-White (WPW) syndrome. Catheter ablation of the accessory pathway eliminates PAF in some patients, but PAF frequently recurs in other patients. The present study was designed to determine prospectively whether P wave signal-averaged electrocardiography (P-SAECG) predicts the recurrence of PAF after successful ablation in patients with WPW syndrome. METHODS AND RESULTS: Forty-six patients with WPW syndrome who had episodes of PAF were prospectively followed. SAECG recording was performed on day 7 after successful ablation of the accessory pathway at study entry. Abnormal P-SAECG for the prediction of recurrence of PAF was defined as a filtered P wave duration > 130 msec. Eleven patients had an abnormal P-SAECG (group 1), whereas 35 patients (group 2) did not. The two groups did not differ in terms of gender, age, left atrial dimension, and atrial vulnerability as determined by electrophysiologic study. During follow-up (40 +/- 19 months), the recurrence of PAF was noted in 10 (91%) of 11 patients in group 1, whereas it was observed in only 2 (6%) of 35 patients in group 2. Kaplan-Meier analysis revealed that the recurrence of PAF was significantly more frequent in group 1 than in group 2 (log rank test, P < 0.0001). By multivariate analysis, filtered P wave duration >130 msec was an independent predictor of recurrence of PAF after ablation (Chi-square = 21.5, P < 0.0001). CONCLUSION: The results of this study indicate that P-SAECG may be useful for identifying patients at risk for recurrence of PAF after successful ablation of WPW syndrome.