2.2. Ablation Procedure
The procedures were mostly performed under conscious sedation, but it was done under general anesthesia in 7 cases. Transvenous multipolar catheters were placed into the cardiac chambers appropriate for the arrhythmia being studied (right and/or left ventricular [RV and/or LV]). LV mapping was performed via the retrograde aortic or transseptal approach. When necessary, an epicardial approach using a percutaneous subxiphoid puncture was attempted at the beginning of the procedure as previously described.10 Electroanatomic mapping systems such as CARTO3 (Biosense Webster, Diamond Bar, CA, USA) or Ensite (Abbott, ST. Paul, MN, USA) were used. Intracardiac echocardiography assisted in defining the anatomical structures, monitoring for potential complications, and performing transseptal punctures. Systemic anticoagulation was achieved with intravenous heparin targeted to a minimum activation clotting time of 350 seconds during LV and 250 seconds during RV mapping. The radiofrequency current was delivered with a 3.5-mm open irrigated tip catheter, with power settings of 30 to 50 W and a temperature limit of 43℃. Contact force sensing catheters were used by the operators while aiming for a 5-30g contact force.