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.