2.4 Ablation procedure
Ablation was guided by the CARTO 3 mapping system, and RF energy was applied by means of a 3.5-mm open-irrigated-tip catheter (Navistar ThermoCoolSmartTouch SF; Biosense Webster) at an irrigation flow rate of 17–30 mL/min, power of 25–35 W, and temperature of 45℃, under sedation achieved by continuous infusion of propofol and dexmedetomidine and intermittent administration of fentanyl. RF was delivered point-by-point with a target contact force of >10 g, target ablation indices of 450 at the anterior wall and 400 at the posterior wall, and an inter-lesion distance of <6 mm. A real-time automated tagging module (VisiTag Module, CARTO3; Biosense Webster) was used to assist in the creation of a contiguous PVI circle. The ipsilateral PVs were ablated circumferentially, and successful PVI was affirmed by absence of LA conduction. At least 30 minutes after PVI, 30 mg of adenosine triphosphate was injected to confirm PV conduction block. Electrograms were recorded on a LabSystem PRO (Bard Electrophysiology, Lowell, MA, USA).