Ablation procedure
Anti-arrhythmic drug (AAD) therapy was stopped at least five half-lives before the ablation. Patients on oral anticoagulation stopped their medications on the day of the ablation. Study patients underwent transesophageal echocardiography to ensure no thrombus in the atrium or left atrial appendage 24h before the ablation.
A 7Fr 20-pole 3-site mapping catheter (BeeAT, Japan Lifeline, Tokyo, Japan) was inserted into the coronary sinus (CS) via the right jugular vein. IDF could be performed with the a BeeAT catheter. Further, catheters were introduced percutaneously through the femoral vein, and a transseptal puncture was performed after verifying the absence of a patent foramen ovale to access the LA. After the transseptal access, a bolus of intravenous heparin (5,000 IU) was administered, with an additional bolus to maintain an activated clotting time of more than 350 s.13 We used propofol and dexmedetomidine during ablation to obtain deep sedation. We used high dose ISP with a continuous administration to investigate the trigger of the AF before the RFCA. If AF was not present, we effectively induced AF artificially by high rate burst pacing during an ISP infusion. After the AF sustained for more than two minutes, IDF was performed to restore SR. After that, we identified the earliest site of the trigger PAC with spontaneously occurring AF. If reproducible, the trigger was identified as an AF foci. We performed a PVI in all patients. When we detected non-PV foci, we added a focal ablation to that site. After the RFCA, we used high dose ISP and high rate burst pacing to artificially induce AF. After the AF was artificially induced, we again performed IDF with 1 to 30 J to restore SR. The endpoint of our ablation was the absence of spontaneous AF occurring after the ISP infusion.
All the patients underwent an enlarged PVI in order to achieve voltage abatement of the electrograms in the encircled areas. Radiofrequency current was delivered with an irrigated-tip ablation catheter (FlexAbilityTM; Abbott, Minneapolis, MN or Thermocool, Biosense Webster, Inc., Diamond Bar, CA, USA) through another long sheath under the guidance of a 3-dimensional (3D) cardiac mapping system (EnSite PrecisionTM, Abbott or CARTO3, Biosense Webster).