Ablation Strategy
All ablation procedures were performed under general anesthesia. Femoral
site access was
obtained, and intravenous heparin was administered to maintain activated
clotting times >350 s.
Radiofrequency (RF) ablation :
After performing a double transseptal puncture, a Lasso or
Penta Ray 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 a pre-acquired CT
scan. A 4-mm open-tip irrigated RF catheter with a contact force sensor
(Thermocool SmartTouch, Biosense-Webster) was then positioned in the
left atrium: PVI was performed using a 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 at all sites. Esophageal temperature was
monitored, and the RF delivery paused if the esophageal temperature
increased by 0.5°C.