Impact of pulsed field ablation for atrial fibrillation on left atrial remodeling at mid – term follow -up

Background Pulsed field ablation (PFA) is a non-thermal type of ablation for atrial fibrillation (AF), yet its impact on left atrial (LA) remodeling remains incompletely defined. Purpose The aim of this study was to compare the changes in LA volume and function before and after PFA. Methods Consecutive patients with paroxysmal or persistent AF undergoing PFA as index ablation were prospectively enrolled between April 2024 and May 2025. Transthoracic echocardiography was performed within 2 weeks pre-ablation and 1-3 months post-ablation. LA volumes and derived indices (LA ejection fraction (LAEF) and phasic functions (reservoir, conduit, contractile)) were measured by two – dimensional (2DE) and three- dimensional (3DE) echocardiography. LA strain parameters were assessed by speckle tracking echocardiography. Changes between baseline and follow-up were assessed using paired statistical tests as appropriate. Results Forty-seven patients were included (66.9±9.4 years; 68.1% male gender), among whom 20 (42.6%) patients had persistent AF. LA maximum volume did not change significantly post-PFA by either 2DE (p = 0.264) or 3DE (p = 0.279). LA minimum volume showed a non-significant trend towards increase on 2DE (42.7 ± 21.1 ml vs. 49.8 ± 28,6 ml, p = 0.076) while a significant increase was observed on 3DE assessment (39.5 ± 17.4 ml vs 43.3 13.3 ml, p = 0.035) (Figure 1). LAEF decreased significantly on both 2DE (44.5 ± 14.1% vs. 40.0 ± 13.2%, p = 0.041) and 3DE (43.0 ± 10.7 % vs. 37.9 ± 7.9 %, p = 0.016). Volumetric reservoir and contractile functions declined significantly post- PFA (2DE reservoir 92.6 ± 56.2 % vs. 74.5 ± 37.9 %, p =0.044; 3DE reservoir 86.7 ± 39.2% vs. 65.7 ± 22. 4%, p = 0.008; 2DE contractile 34.7 ± 14.5% vs. 23.3 ± 11.9%, p< 0.001, 3DE contractile 33.3 ± 9.8 % vs 25.5 ± 9.4%, p <0.001), whereas conduit function did not change significantly either by 2DE (p=0.057) or 3DE echocardiography (p=0.054) (Figure 2). Strain analysis showed no significant change in LA reservoir (p=0.344) or contractile strain (p=0.098), but a significant reduction in LA conduit strain (-10.5 ± 4.0 % vs -8.1 ± 3.7 %, p<0.001). Conclusion PFA was associated with early LA remodeling characterized by increased LA minimum volume and reduced volumetric LA performance despite stable LA maximum volume, with a selective decline in LA conduit strain. Larger studies with serial imaging are warranted to define recovery trajectories and prognostic implications.Figure 1.LA volumes before and after PFAFigure 2.