Procedure
In all patients, the procedure was performed under deep sedation with a continuous intravenous infusion of dexmedetomidine hydrochloride (Precedex) and additional boluses of midazolam and thiamylal. Esophageal temperature was monitored throughout the procedure; temperature limit was set to 41℃. If a patient showed AF rhythm in the electrophysiological laboratory, electric cardioversion was performed to restore sinus rhythm.
A bolus of 5,000–10,000 international units of unfractionated heparin (100-150 U/kg) was administered before trans-septal puncture to achieve activated clotting time (ACT) >300 sec. ACT was measured every 20 min after the first heparin shot and additional heparin boluses were administered to maintain the ACT >300 sec. A decapolar catheter was advanced into the coronary sinus via the internal jugular vein. An 8Fr ICE catheter (SoundStar, Biosense Webster, Diamond Bar, CA, USA) was inserted into the right atrium (RA) via a 10Fr short sheath in the right femoral vein; trans-septal puncture was performed under ICE guidance. Two 8Fr long sheaths (SL1; Abbott, St. Paul, MN, USA) and a 8.5Fr deflectable sheath (Agilis NxT, [short size 61 cm], Abbott, St. Paul, MN, USA) were then advanced into the LA. A ring-shaped decapolar catheter (LASSO® eco catheter, Biosense Webster, Diamond Bar, CA, USA) and a multielectrode catheter (PENTARAY® eco catheter, Biosense Webster) were used for mapping. CARTO V6 (Biosense Webster) was used to create a 3-dimensional electro-anatomical voltage map of the LA and to integrate the voltage map with the CT imaging reconstruction of the LA (CartoMerge, Biosense Webster). The contrast fluoroscopy image of the LA was obtained and combined with the reconstructed CT image by CARTOUNIVU™ Module (Biosense Webster).