The purpose of this study is to investigate the appropriate duration of dabigatran use after radiofrequency catheter ablation for paroxysmal atrial fibrillation in patients with low thromboembolic risk. According to the most recent guideline, anticoagulation is recommended to continue at least 2 months after the procedure. However bleeding risk with anticoagulant is also problematic. Post-procedural thrombosis is considered due to acute inflammation or char formation at the site of ablation, and these reaction occurs mostly within 1 month after the procedure. Also, the risk of thromboembolism is low in patients with CHA2DS2-VASc score less than 1. The investigators hypothesized that dabigatran use for the first 1 month after the RFCA for patients with paroxysmal AF and low thromboembolic risk would be sufficient for efficacy and safety compared to conventional dabigatran use for 2 months.