Impact of pulsed field ablation for atrial fibrillation in left atrial function

Background Pulsed field ablation (PFA) is a novel, non-thermal and selective atrial fibrillation (AF) ablation modality based on irreversible electroporation. It enables the creation of transmural and durable lesions while minimizing collateral damage. Its impact on left atrium (LA) mechanical function, however, remains incompletely studied. Purpose The aim of this study was to evaluated the effects of PFA on LA function in patients undergoing AF ablation. Methods This prospective observational study included all patients undergoing AF ablation with PFA between March 2025 and January 2026. LA function was assessed using LA strain (LAS) before the procedure (T1), the day after (T2), and at 3-month follow-up (T3). The primary endpoint was the temporal change in LAS across the 3 time points. Secondary analysis compared differences in LAS variation between patients undergoing pulmonary vein isolation (PVI) alone versus PVI plus additional posterior wall (PW) lesions. Results A total of 100 patients were included (33% female; mean age 65 ±7,9 years; 63% persistent AF). In addition to PVI, 23% of patients had additional PW lesions. Median LA volume was 40 mL/m² (34–48) and median LVEF was 59% (55–62). The proportion of patients in sinus rhythm (SR) differed significantly across the three time points (65.1% at T1, 98.9% at T2, 92.1% at T3). In the overall cohort, linear mixed-effects modelling showed no significant changes in reservoir LA strain (LArS) immediately after ablation (T2) compared with baseline (T1) (19.3% [95%CI 9.0; 29.6] vs 20.1% [95%CI 9.6; 30.5], p=1,000). However, LArS significantly increased at T3 (22.6% [95%CI 12.3; 32.9] p T2–T3=0.004). Among patients in SR, baseline LArS was higher (23.9%, 95%CI 6.2–41.6). After ablation, LArS significantly decreased (19.5%, 95%CI 4.4–34.5; p<0.001) and recovered at T3 to values comparable to baseline (22.5% [95%CI 1.5; 46.5]; pT2–T3=0.008; pT1–T3=0.696). Contractile LAS (LActS) showed a similar pattern, whereas conduit LAS remained unchanged. Compared with PVI alone, patients receiving additional PW lesions had larger LA volumes (46.3 [IQR 39–60] vs 39 [IQR 33–47], p=0.009) and lower T1 LArS (13.1% [IQR 10.2–17.6] vs 19.7% [IQR 15.8–27.8], p<0.001). Additional PW lesions were associated with poorer LActS recovery at T3 (ΔLActST3–T2 = -3.9% [95%CI -2.5 to -5.4] for PVI vs 0.6% [–2.9 to 4.1] for PVI+PW, p=0.022). Despite a similar trend for LArS, the difference between groups did not reach statistical significance (p=0.059). Conclusion AF ablation with PFA resulted in a transient reduction in LArS, that fully recovered at 3 months. Additional PW lesions were associated with poorer LActS recovery at 3 months, compared with PVI alone.