Electrophysiologic study and catheter ablation
All antiarrhythmic drugs except for amiodarone were discontinued for at least five half-lives before the ablation. Warfarin was administered with a target international normalized ratio of 2.0-3.0 in patients under 75 years old or 1.6-2.5 in patients 75 years or more for at least one month before the procedure and continued during the periprocedural period. Direct oral anticoagulants (DOAC) were used for at least one month before the procedure and continued during the periprocedural period except for the procedure morning. The absence of atrial thrombi was confirmed by transesophageal echography or enhanced computed tomography. CA was performed under deep sedation using midazolam and dexmedetomidine. We deployed a multielectrode catheter into the coronary sinus from the jugular vein and circumferential decapolar electrode catheter in the pulmonary veins. Boluses of 80 and 50 IU/kg heparin were administered after venous and transseptal punctures. The activated clotting time was evaluated at least every 30 minutes and maintained at ≥300 seconds during the procedure. Pulmonary vein isolation was performed guiding by a circumferential decapolar electrode catheter. We monitored the surface electrocardiogram (ECG) and bipolar intracardiac electrograms on a computer-based digital amplifier recording system (RMC-5000, Nihon Kohden). Ablation was performed with a non-irrigation catheter (Navistar, Biosense Webster Inc) or irrigated-tip catheter (SmartTouch, Biosense Webster Inc. or FlexAbility, Abbott). A CARTO electroanatomical mapping system (Biosense Webster Inc) or Ensite Velocity system (Velocity Abbott) was used. The endpoint of the ablation was the complete isolation of all four pulmonary veins (PVs). Whether to create linear lesions, isolate the superior vena cava, and ablate the complex fractionated atrial electrograms (CFAEs) and non-PV triggers were left to the discretion of each operator.