Ensite

PVI was performed with the AutoMark system (EnSite; Abbott). The FTI and LSI were calculated only when the ablation catheter stayed within the confined area. FTI was defined as the total CF integrated over the time of RF delivery, and the LSI was derived from a mathematical expression that incorporates CF, power and duration of RF application. AutoMark settings for filter thresholds were as follows: for catheter position stability, the minimum marker time was 4 seconds, the marker spacing was 4 mm, and the away time was 5 seconds.

All procedures were performed under mild-to-moderate conscious sedation using dexmedetomidine, fentanyl, and thiopental. All patients had continuous arterial blood pressure monitored with an arterial line and received oxygen (5 L/min) either with a face mask or noninvasive positive-pressure ventilation in case of sleep apnea syndrome. Our usual practice has been to skip anticoagulation on the morning of CA, except for patients on warfarin or patients on direct oral anticoagulant with a history of stroke or low left atrial appendage blood flow velocity. Unfractionated heparin was administered during the left heart CA to maintain the activated clotting time (ACT) of ≥300 seconds. Diagnostic catheters were introduced via femoral and internal jugular veins and positioned at the coronary sinus (CS), tricuspid annulus, His recording site, and right ventricle (RV) apex according to the physician’s decision. A 3-dimensional electroanatomic mapping system was created using CARTO (Biosense Webster, Diamond Bar, CA), Ensite (Abbott Laboratories, Chicago, IL), or Rhythmia (Boston Scientific, Cambridge, MA), except in patients who were ablated using the cryoballoon system. As per our safety protocol, we used intracardiac echocardiography (ICE) just for the transseptal puncture and usually remove it prior to the insertion of the ablation catheter to minimize venous access.

The procedures were mostly performed under conscious sedation, but were under general anesthesia in 7 cases. Transvenous multipolar catheters were placed into the cardiac chambers appropriate for the arrhythmia being studied (right and/or left ventricular [RV and/or LV]). LV mapping was performed via the retrograde aortic or transseptal approach. When necessary, an epicardial approach using a percutaneous subxiphoid puncture was attempted at the beginning of the procedure as previously described.¹² Electroanatomic mapping systems such as CARTO3 (Biosense Webster) or Ensite (Abbott) were used. Intracardiac echocardiography assisted in defining the anatomical structures, monitoring for potential complications, and performing transseptal punctures. Systemic anticoagulation was achieved with intravenous heparin targeting a minimum activation clotting time of 350 s during LV and 250 s during RV mapping. The RF current was delivered with a 3.5‐mm open irrigated tip catheter, with power settings of 30–50 W and temperature limit of 43°C. Contact force sensing catheters were used by the operators while aiming for a 5–30 g contact force.