Abstract: 【Objective】 To explore P wave duration to predict the recurrence postablation in paroxysmal atrial fibrillation patients.【Methods】 Totally 171 paroxysmal atrial fibrillation patients undergoing circumferential pulmonary vein isolation were included in this study. The electrocardiogram before and after ablation were recorded. The P wave duration in lead Ⅱ

Ⅲ

aVF and V1 were measured

the change value of P wave duration were calculated. 【Results】 P wave duration was significantly shortened in lead Ⅱ

Ⅲ and V1 after ablation (P < 0.001). All patients were divided into recurrence group (n = 32) and non-recurrence group (n=139). Compared with non-recurrence group

the change value of P wave duration in lead Ⅱ

Ⅲ and V1 were smaller (P < 0.01). There was no significant difference in P wave duration before or after ablation and other indications between two groups. Multivariate analysis showed that the smaller change value of P wave duration in lead Ⅱ(P < 0.001

OR = 0.73

95% CI 0.648-0.824) and Ⅲ (P = 0.006

OR = 0.904

95% CI 0.840-0.972) were independent predictors of atrial fibrillation recurrence. The change value of P wave duration in lead Ⅱ is superior to lead Ⅲ in predicting atrial fibrillation recurrence after ablation (P = 0.01). Using -2.21ms as the best cutoff

change value in lead Ⅱ had a 85.29% sensitivity and a 83.94% specificity. Using 0ms as the cutoff

the change value in lead Ⅱ had a 65.62% sensitivity and a 91.37% specificity. 【Conclusion】 Change value of P wave duration in lead Ⅱ can better predict atrial fibrillation recurrence after radiofrequency ablation.