Reversible posterior wall electroporation following pentaspline versus balloon-in-basket pulsed-field ablation

Background Pulsed-field ablation (PFA) can result in both reversible and irreversible electroporation. Consequently, acute electroanatomical re-mapping after pulmonary vein isolation (PVI) may overestimate lesion durability and may influence intra-procedural decision-making, particularly when considering additional posterior wall (PW) ablation to prevent the persistence of narrow, proarrhythmic conduction channels. Comparative data on lesion reversibility across different systems remain limited. Purpose To assess lesion reversibility after PFA by analysing differences between acute and chronic electroanatomical mapping (EAM) findings in patients undergoing scheduled systematic remapping following an index PFA procedure performed with two distinct catheter technologies. Methods We conducted a prospective, single-centre study including 80 consecutive patients undergoing PFA for paroxysmal or persistent atrial fibrillation (AF) using either a pentaspline catheter (P-PFA; n=30) or a balloon-in-basket catheter (BiB; n=50). Each system was paired with its respective EAM platform. Acute remapping was performed with the ablation catheter, and chronic remapping (≥30 days) with a high-density diagnostic catheter. The primary endpoint was PW lesion reversibility, defined as the difference in PW surface area with bipolar voltage <0.1 mV between acute and chronic remapping. Continuous variables were compared using t-test or Wilcoxon test as appropriate. Results Time to remapping was comparable between groups (38.0 [34.0–51.2] vs 44.0 [35.0–57.0] days; p=0.280). BiB was associated with shorter total procedure time (60.5 [53.0–68.8] vs 69.0 [61.5–77.0] min; p=0.014), left atrial time (39.5 [35.0–45.8] vs 54.0 [46.0–58.8] min; p<0.001) and fluoroscopy time (4.83 [3.18–5.95] vs 8.15 [6.13–9.44] min; p<0.001). The number of applications was lower with BiB (15.0 [14.0–16.0] vs 58.0 [51.8–68.5]; p<0.001). Acute electrogram density did not differ between systems (1441.1 ± 553.9 vs 1341.3 ± 321.6 points; p=0.388). Chronic electrogram density was significantly higher in the P-PFA group (5554.0 [4342.0–6932.0] vs 4035.0 [3063.2–5079.8] points; p<0.001). Lesion reversibility (acute minus chronic PW ablated area) was significantly greater with P-PFA (6.8 [4.6–11.2] cm²) compared with BiB (−0.1 [−1.4–1.9] cm²; p<0.001). Acute PW ablation area was larger with P-PFA (13.3 [9.9–16.5] vs 4.3 [2.3–7.8] cm²; p<0.001). Chronic PW ablation area was comparable between systems (5.6 [3.8–7.6] vs 5.0 [3.0–7.0] cm²; p=0.29). Conclusion P-PFA generates larger acute PW ablation areas but shows substantial lesion reversibility, resulting in chronic PW surfaces comparable to BiB. In contrast, BiB demonstrates greater stability between acute and chronic lesion dimensions. These findings suggest distinct lesion dynamics between PFA technologies, with potential implications for procedural strategy and interpretation of acute remapping findings.