2.2 Pre-ablation preparation protocol
Prior to the procedure, all antiarrhythmic drugs were discontinued for at least 5 half-lives. Direct oral anticoagulants were changed to dabigatran from the day before the ablation. Patients on warfarin continued taking it during the peri-procedural period. An international normalized ratio level between 2.0 and 3.0 was considered acceptable. All patients continued taking anticoagulants throughout the peri-procedural period. Using prone-positional enhanced computed tomography or intracardiac/transesophageal echocardiography, we confirmed that there were no intracardiac thrombi before the ablation. Surface electrocardiograms and bipolar intracardiac electrograms filtered from 30 to 500 Hz were monitored.
Ablation was performed under general anesthesia with dexmedetomidine, thiopental, and rocuronium. The ablation procedure has been previously described in detail.15 Briefly, a standard transvenous approach was employed for transseptal puncture and subsequent PV isolation. A 7-Fr 20-pole three-site mapping catheter (BeeAT; Japan Lifeline, Tokyo, Japan) was located in the coronary sinus for anatomic guidance. With a radiofrequency needle (Baylis Medical, Montreal, QC, Canada), a single transseptal puncture of the fossa ovalis was performed using the Brockenbrough technique. The puncture was guided by intracardiac echocardiography (ACUSON AcuNav; Biosense Webster, Diamond Bar, CA, USA) and biplane fluoroscopy (right and left anterior oblique projections). Thereafter, heparin was administered intravenously to achieve an activated clotting time between 300 and 350 seconds during the ablation procedure.