CONGRESS ABSTRACT

Background Pulsed field ablation (PFA) represents a significant improvement in the field of atrial fibrillation (AF) ablation. Nonetheless, PFA by using standard procedural protocol showed a similar efficacy as compared with thermal ablation. The aim of this study was to verify whether the systematic use of high-density (HD) mapping at the end of the PFA standard protocol can help to identify non-optimal pulmonary veins isolation (PVI), not evident with the use of the ablation catheter alone, and potentially responsible for the suboptimal efficacy of the procedure. Methods We performed a retrospective analysis of all consecutive patients treated with PFA for PVI at our center between January 2024 and November 2024. Patients in whom a post ablation HD mapping was not performed were excluded. PVI was performed using a penta-spline catheter and a standard protocol with at least 8 applications per pulmonary vein. The primary outcome was the percentage of patients in whom HD remapping highlighted the suboptimal isolation of at least one pulmonary vein, not evident with the use of the ablation catheter alone, leading to subsequent PFA application. Predictors of this outcome were also studied with univariate logistic regression analyses. Results During the enrolling period 55 patients were treated with PFA for PVI at our center. Among these, 31 patients (56%) underwent HD remapping. The mean age was 61±11 years, 24 (77%) were male, 17 (55%) had paroxysmal AF, 14 (45%) an history of structural heart disease, and 9 (29%) were “redo” procedure. The media left ventricle ejection fraction was 57% (IQR 50-60%), and the median left atrium volume index was 46 ml/m2 (IQR 38-62 ml/m2). HD remapping highlighted a suboptimal isolation of at least one pulmonary vein in 8 patients (26%, 95%CI 12-45%). Total procedure time (p=0.30) and radiation exposure (p=0.54) were not significantly higher in patients who underwent HD remapping. Among the possible predictors studied, although it did not reach statistical significance, only LAVI showed a trend towards an increased risk of incomplete PVI (OR 1.06, 95%CI 0.997-1.14, p=0.063). Conclusion In our single-center analysis, a non-negligible percentage of patients treated with standard PFA protocol showed a suboptimal PVI on HD remapping that was not evident with the ablation catheter alone. Despite our findings suggest the importance of HD remapping, further studies are needed to evaluate their clinical and prognostic significance.