Impairment of left atrial function following pulsed-field ablation for persistent atrial fibrillation

Introduction Pulsed-field ablation (PFA) represents a highly effective non-pharmacological treatment of atrial fibrillation (AF). The effect of ablation beyond pulmonary vein isolation (PVI) on the mechanical function of the left atrium (LA) remains unknown. Purpose To assess changes in LA function—reservoir, conductive, and contractile strain—using transthoracic echocardiography (TTE) and nuclear magnetic resonance (MRI) after PFA for AF, including PVI and posterior wall ablation. Methods Patients with persistent AF who maintained sinus rhythm for at least two months prior to ablation were included in the study. The main exclusion criteria were a history of left atrial ablation or a LA diameter exceeding 60 mm. The ablation procedure involved PVI and posterior wall ablation, utilizing the FARAPULSETM system. Cardiac late-gadolinium MRI was performed within two weeks before the ablation and again three months after the procedure. TTE was conducted one day before the ablation, as well as one day and three months after the procedure. Speckle tracking (TTE) and feature tracking methods were used to analyze LA function via TTE and MRI, respectively. All measurements were conducted while the patient was in sinus rhythm; if this was not achievable, the subject was excluded from the analysis. The primary endpoint was the change in LA reservoir function, conductive function, and contractile function over time, as assessed by TTE and MRI. Results A total of 29 patients with persistent AF were included in the study, with a mean age of 66 years (± 9.8), of whom 11 patients (38%) were female. Immediately after the ablation procedure, TTE showed a significant decline in both reservoir function (19.6 [± 5.8] to 15.9 [± 5.9], p < 0.001) and contractile function (-9 [± 3.5] to -4.8 [± 2.9], p < 0.001). Among the 23 patients who completed a 3-month follow-up, the significant changes in reservoir function (p = 0.01) and contractile strain (p < 0.001) were maintained. Furthermore, MRI analysis demonstrated a significant decline in reservoir function (15.01 [± 3.85] to 12.32 [± 2.98], p = 0.001) and contractile strain (-5.87 [± 2.75] to -2.81 [± 2.02], p < 0.001). Notably, in 28 out of 29 patients (96%), new late gadolinium enhancement was observed in the posterior wall three months after the ablation. Conclusion Nuclear magnetic resonance and echocardiographic analysis showed a persistent decline in both reservoir and contractile left atrial strain following pulsed-field ablation for persistent atrial fibrillation. Additionally, new late-gadolinium enhancement was detected in 96% of patients.