RF ablation
All ablation procedures were performed under general anesthesia. Femoral site access was
obtained, and intravenous heparin administered to maintain activated clotting times >350 s.
After performing a double transseptal puncture, PentaRay mapping catheter (Biosense-Webster, Diamond Bar, California) was positioned in the left atrium. An electroanatomic map of the left atrium was obtained using the CARTO system (Biosense-Webster) and superimposed on pre-acquired CT scan. A 4-mm open-tip irrigated RF catheter (Thermocool or Thermocool SmartTouch, Biosense-Webster) was then positioned in the left atrium: PV isolation (PVI) was performed using real-time automated display of RF application points (Visitag, Biosense-Webster) with predefined catheter stability settings. Starting energy delivery parameters were 25 to 40 W on the posterior wall and 35 to 45 W at other sites. Target contact force was between 5 and 20 g for cases performed after 2014 with the Thermocool Smart Touch catheter. Esophageal temperature was monitored, and the RF delivery paused if the esophageal temperature increased by 0.5°C. Electric isolation of PVs was confirmed by entrance block to individual PVs, assessed by PentaRay catheter positioned at the PV antrum.