It has been demonstrated that a prolonged PR interval is associated with an increased risk of AF. However, the impact of a prolonged PR interval on recurrence of paroxysmal atrial fibrillation (AF) after catheter ablation is not clear. A total of 112 patients with a prolonged PR interval (PR > 200 ms) (PPR group) and 112 age- and gender-matched control patients (on a 1:1 basis) with a normal PR interval (NPR group) were included in this study. AF recurrence was defined as the occurrence of confirmed atrial tachyarrhythmia lasting more than 30 seconds beyond 3 months after catheter ablation in the absence of any antiarrhythmic treatment During a mean follow-up period of 10.9 +/- 5.5 months (range, 3-18 months), 61 patients (27.2%) developed recurrence of AF. The recurrence rate was higher in the PPR group than in the NPR group (33.9% versus 20.5%, respectively; P = 0.018). Cox regression analysis with adjustment for age, body mass index, valvular heart disease, left atrial diameter, and pulmonary vein isolation identified only a prolonged PR interval as an independent predictor of recurrence of AF (hazard ratio, 1.81; 95% confidence interval, 1.07-3.05; P = 0.027). Patients with a prolonged PR interval were at an increased risk of AF recurrence after catheter ablation.