PVI Procedure
The procedure was performed under sedation with intravenous dexmedetomidine. A temperature probe (SensiThermTM; St. Jude Medical) for monitoring the oesophageal temperature was inserted via the nasal fossa and placed between the level of the superior and inferior pulmonary veins. Arterial access was routinely acquired for continuous blood pressure. A total of 3,000 units of heparin were administered after both arterial and venous access was obtained. A total of 2,000 units of heparin were administered following transseptal puncture. Heparinised saline was also infused to maintain an activated clotting time of 300–350 seconds. Ablation catheters were inserted from the right atrium (RA) to the LA via the atrial septum. Under the guidance of three-dimensional electroanatomic mapping (CARTO 3 version 7.0; Biosense Webster, Inc., California, USA), RF energy of 25–30 W was applied using a quadripolar 3.5-mm-tip irrigation catheter (Thermocool, Biosense Webster, Diamond Bar, CA, USA). The target ablation index was 400 in the right PVs and anterior of the left PVs and 350 in the posterior of the left PVs, except for the perioesophageal. After the successful achievement of bidirectional conduction block between the PVs and LA, PVI was reconfirmed by waiting for at least 30 minutes of the observational period.