Catheter ablation procedure
We discontinued all antiarrhythmic drugs (AADs) ≥ 3 days before ablation, except for amiodarone, which was stopped ≥ 1 month before. Patients underwent transesophageal echocardiography (TEE) the day before the procedure to exclude the presence of thrombi.
Electrophysiological studies and catheter ablation were performed under intravenous sedation with dexmedetomidine or propofol, with the latter performed by one of four experienced operators (M.M, T.K, A.S, and Y.M). Most of the patients underwent radiofrequency catheter ablation. Cryoballoon ablation was performed for persistent AF of short standing. Patients with common PVs or a large PV diameter underwent radiofrequency catheter ablation.
In cryoballoon ablation, an Arctic Front Advance cryoballoon catheter with a 28-mm balloon size (Medtronic, Inc., Minneapolis MN, USA) was passed into each PV under guidance by fluoroscopy and the 3-D mapping system. After confirming PV occlusion by pulmonary venography, cryoablation commenced and continued for 180 s, during which individual PVs were isolated. If LA–PV conduction persisted after cryoballoon ablation, an additional touch-up ablation was performed using an open-irrigated Thermocool SmartTouch (Biosense Webster) or FlexAbility (St. Jude Medical) linear ablation catheter with a 3.5-mm tip.
In radiofrequency catheter ablation, circumferential ablation around both ipsilateral PVs was performed using an open-irrigated Thermocool SmartTouch (Biosense Webster) or FlexAbility (St. Jude Medical) linear ablation catheter via an Agilis or Swartz Braided SL0 Transseptal Guiding Introducer Sheath (St. Jude Medical). Radiofrequency energy was applied for 30 s at each site using a maximum temperature of 42°C, maximum power of 35 W, and flow rate of 17 mL/min. PV isolation was considered complete when the 20-pole circular catheter no longer recorded any PV potentials.
We allowed additional ablation procedures in this study as recommended by the guidelines at the discretion of the operator, such as focal ablation for reproducible non-PV triggers; ablation of linear lesions, complex fractionated atrial electrograms (CFAE), and LVA homogenization; superior vena cava (SVC) isolation; and cavotricuspid isthmus linear ablation if patients had clinical or induced typical atrial flutter.