Mapping and Ablation protocol
All antiarrhythmic drugs were discontinued for at least 5 half-lives prior to ablation. All patients took direct oral anticoagulants (DOAC) or warfarin for at least 1 month prior to the procedure. Computed tomography was performed to evaluate the cardiac anatomy.
During the procedure, the surface electrogram and intracardiac electrograms were continuously monitored and stored on a computer-based digital recording system. All ablation procedures were performed under deep sedation with dexmedetomidine hydrochloride, propofol, and pentazocine. A 100U/kg body weight dose of heparin was administered after securing the venous line, and the activated clotting time was maintained at 300 to 350 seconds.
Mapping and ablation were performed under the guidance of a three-dimensional (3D) mapping system (CARTO3®; Biosense Webster, Irvine, CA, USA). A duodecapolar catheter (Map-iTTM, ACCESS POINT, Rogers, MN, USA) was placed into the coronary sinus (CS). A duodecapolar catheter with five branches (Pentaray®; Biosense Webster, Irvine, CA, USA) was used to construct a 3D map of the SVC. An open-irrigated 3.5 mm tip electrode catheter (Thermocool SMARTTOUCH®; Biosense Webster, Irvine, CA, USA) was utilized for the ablation.