2.3. CA procedure

All procedures were performed while patients were under conscious sedation and local anesthesia. CA was performed in all cases with wide antral circumferential until the entrance and exit block was demonstrated for each pulmonary vein. With a three-dimensional electroanatomical mapping system (CARTO R^@ 3; Biosense Webster, Irvine, CA, USA), the ablation catheter (Thermocool SMARTTOUCH; Biosense Webster) was inserted into the LA to perform radiofrequency ablation. The mapping catheter was used to record pulmonary vein potentials (Lasso^® NAV Eco; Biosense Webster). Circumferential ablation in both the left and right pulmonary veins was confirmed. No additional ablation lines or complex fractionated atrial electrogram ablation was performed in this study. Sinus rhythm was restored by either ablation or electric cardioversion.