Posterior Pulmonary Vein Isolation Lesion Spacing and Left Atrial Posterior Wall Narrowing During Pulsed Field Ablation

ABSTRACT Background Left atrial posterior wall (LAPW) narrowing after excessive extension of bilateral pulmonary vein isolation (PVI) lines during pulsed field ablation (PFA) may create a proarrhythmic substrate. The CARTO 3‐integrated variable‐loop circular catheter (VLCC) provides real‐time tissue proximity indication (TPI) and ablation‐tag location, but their relationship with LAPW narrowing remains unclear. Therefore, we evaluated associations of TPI status and inter‐tag distance (ITD) with acute LAPW narrowing and whether an ITD‐guided workflow was associated with LAPW preservation. Methods Fifty‐two retrospective and 27 prospective atrial fibrillation patients underwent PFA using a VLCC. In the retrospective phase, we evaluated the association between ITD, measured using TPI‐positive tags and all tags, and LAPW narrowing (< 10 mm) and derived a cutoff. In the prospective phase, the ITD‐guided workflow was applied, and we assessed residual LAPW band width. Results In the retrospective phase, both TPI‐positive‐tag ITD and all‐tag ITD correlated with LAPW band width ( r = 0.63 and 0.70, respectively; both p < 0.001). All‐tag ITD showed a numerically higher AUC for LAPW narrowing than TPI‐positive‐tag ITD (0.869 vs. 0.795; p = 0.099), with an optimal all‐tag ITD cutoff of 16.5 mm. In the prospective phase incorporating the all‐tag ITD cutoff, residual LAPW band widths were wider at the roof (19.4 ± 7.9 vs. 25.1 ± 7.1 mm; p = 0.002) and carina (13.6 ± 7.1 vs. 20.8 ± 8.0 mm; p < 0.001) than in the retrospective phase. Conclusions An all‐tag ITD‐guided workflow was associated with greater preservation of the residual LAPW band width.