Ablation Procedure
In paroxysmal AF patients, pulmonary vein isolation (PVI) was performed using either cryo-balloon ablation (CBA, single short freezing for 180 sec in each PV) or radiofrequency catheter ablation (RFCA) in the first session. RFCA was selected in patients with common PV or large PV ostium (>28mm) based on the LA/PV anatomy evaluated by cardiac-computed tomography imaging before the procedure. In persistent AF patients, only RFCA was used for PVI in the first session. In all patients, only the PVI strategy was used for the first AF ablation and no additional linear ablation in the LA was performed; only cavotricuspid isthmus ablation was permitted for documented typical atrial flutter. In the second session for both types of AF, the incomplete line of PVI was repaired with RFCA if necessary, and additional linear ablation at the roof and bottom between left and right PV (posterior wall isolation) and superior vena cava isolation were performed.
The CBA procedure was achieved using electro-anatomical mapping (EnSite NavX, Abbott, St. Paul, MN, USA) and fluoroscopic guidance to position the cryo-balloon catheter. In the RFCA procedure, PVI was achieved using a focal “point-by-point” catheter approach, delivering radiofrequency energy to the cardiac tissue with irrigation tip catheters (THERMOCOOL SMARTTOUCH® SF, Biosense Webster, Diamond Bar, CA, USA [target contact force: 10-20g, RF time: 30-60 sec, irrigation flow rate: 8 ml/min for ≤30W, 15 ml/min for >30W, power control mode], or FlexAbilityTM, Abbott, St Paul, MN, USA [RF time: 30-60 sec, irrigation flow rate: 10 ml/min for <38℃, 13 ml/min for ≥38℃, temperature control mode]). RFCA lesion sets encircled the PV antra using electro-anatomical mapping (CARTO3, Biosense Webster, Diamond Bar, CA, USA or EnSite NavX, Abbott, St. Paul, MN, USA) and fluoroscopy guidance.
All procedures were performed under sinus rhythm; internal (3-35J) or external (50-220J) electrical cardioversion was performed with gradually increasing shock intensity to restore sinus rhythm when AF was observed before/during the procedure.