How to isolate the superior vena cava using balloon-in-basket pulsed field ablation system: Standardized workflow and initial results.

Background: Superior vena cava (SVC) is one of the most important non-pulmonary vein (PV) foci in patients with atrial fibrillation (AF), but ablation at this site carries risks of phrenic nerve injury and sinus node dysfunction. Balloon-in-basket (BiB)-pulsed field ablation (PFA) is a novel nonthermal system offering stable wall contact and simultaneous mapping, yet its use for SVC isolation has not been well established. Objective: This study described a standardized workflow and initial results of SVC isolation using the BiB-PFA system. Methods: We included patients who underwent de novo PV isolation and SVC isolation using the BiB-PFA system. SVC isolation was performed using a standardized workflow including electroanatomic mapping, phrenic nerve pacing, selective voltage adjustment (1800 or 1400 V), and systematic remapping. Baseline characteristics, procedural details, and acute safety outcomes were evaluated. Results: A total of 10 patients (median age 78 years, 4 women, and 2 with paroxysmal AF) were analyzed. Acute PV isolation and SVC isolation were achieved in all patients. 1 patient developed transient sinus node arrest immediately after the first application for SVC, which resolved with isoprenaline without pacemaker implantation. No persistent sinus node dysfunction or phrenic nerve palsy occurred. Conclusion: We described a standardized, reproducible strategy for SVC isolation using the BiB-PFA system. In this initial experience, the strategy was feasible and safe, with acute success in all patients and only 1 transient adverse event. These findings suggest that the BiB-PFA system may represent a promising tool for adjunctive SVC ablation in AF.