Left atrial appendage stunning during pulse-field ablation using a variable-loop irrigated circular catheter

Background A high incidence of silent cerebral lesions (SCLs) has been reported after pulse-field ablation (PFA) using a variable-loop irrigated circular catheter (VLCC). Aim This study aimed to evaluate left atrial appendage (LAA) function during PFA using transesophageal echocardiography (TEE) and to explore its potential association with the development of SCLs. Methods We prospectively analyzed 27 patients who underwent de novo pulmonary vein isolation (PVI) for atrial fibrillation (AF) using a VLCC with an irrigation flow rate of 30 mL/min. All procedures were performed under general anesthesia. LAA emptying and filling velocities, which are an indices of LAA function, were assessed using pulsed-wave Doppler before and immediately after PFA applications. In cases where LAA function decreased, follow-up TEE was performed one month after ablation. In addition, the amplitudes of LAA potentials recorded at the distal LAA and the Marshall vein were evaluated during ablation. Brain MRI was performed within 24 hours after the procedure to assess SCLs. Results PVI was successfully achieved in all patients. The mean number of PFA applications was 59±12 per procedure (3 applications per ablation), including 30±5 applications to the left pulmonary veins. Four patients were excluded from the analysis because electrical cardioversion was required due to AF. LAA emptying velocity decreased after PFA (69.9 ± 26.8 vs 49.7 ± 19.8 cm/s, p<0.0001) but recovered at 1 month (49.7 ± 19.8 vs 62.7 ± 14.0 cm/s, p=0.005). In contrast, LAA filling velocity showed a non-significant decrease (58.7 ± 19.8 vs 53.1 ± 18.2 cm/s, p=0.073). The amplitude of LAA potentials recorded from the distal LAA decreased after PFA (4.06 ± 1.78 vs 2.43 ± 1.12 mV, p=0.0004), whereas potentials recorded from the Marshall vein showed no significant change (8.52 ± 4.46 vs 6.39 ± 3.87 mV, p=0.087). SCLs were detected on post-procedural brain MRI in 4 (17%) patients. Patients with SCLs had lower LAA emptying and filling velocities than those without SCLs. Conclusion PFA using a VLCC was associated with a reduction in LAA ejection velocity. SCLs were more likely to occur in patients with impaired baseline LAA function rather than as a consequence of PFA-induced LAA stunning.