3.2 Ablation procedure
Electrophysiological studies and catheter ablation were performed by three experienced operators (M.M, T.K, and Y.M) with the patient under intravenous sedation with dexmedetomidine. The operator performed the mapping and ablation under guidance with an electroanatomical mapping system (CARTO 3®). First, PVI was performed using an open-irrigated ablation catheter (Thermocool SmartTouch®, Biosense Webster), a cryoballoon (Arctic Front Advance®, Medtronic, Minneapolis, MN, USA), or a laser balloon (HeartLight®, CardioFocus, Marlborough, MA, USA). Radiofrequency application was set at 30 W using a dragging technique with a maximum temperature of 42 °C and an irrigation rate of 17 ml/min. The operator attempted to maintain an appropriate contact force between the catheter and endocardium of 5 to 20 g. In cases using a cryoballoon, 180-sec freezing was applied. The laser balloon was inflated with the goal of complete occlusion of the PV ostium. Laser lesions were created with a 30–50% lesion overlap. Where very good tissue contact was obtained, maximal power (12 W for 20 seconds) was chosen. At regions with moving blood, laser energy was applied at 7 W for 30 seconds. PV electrograms were recorded using a 20-pole circular mapping catheter (LassoNaV®, Biosense Webstar). PVI was considered complete when both entrance and exit blocks were created.