The effect of external pre-application prior to pulsed-field catheter insertion on the prevention of microembolic signals assessed by carotid echocardiography

Background Pulsed-field ablation (PFA) is being increasingly utilised owing to its favourable safety profile and efficacy. Asymptomatic cerebral events have been reported in approximately 14% of PFA procedures, frequently attributed to microembolic signals (MESs) detected during the initial pulmonary vein (PV) applications with the PulseSelect system. Purpose This study aimed to identify strategies for reducing MESs during the initial PV applications in PFA using the PulseSelect system. Methods Forty patients with atrial fibrillation undergoing PFA with the PulseSelect system were assigned to two groups: a conventional method group (n=20) and an external pre-application group (n=20). Carotid echocardiography (Figure a) was performed throughout the procedure, and cerebral magnetic resonance imaging was undertaken one day following the procedure. In the external pre-application group, a single pulse application was delivered in a saline pool prior to catheter insertion (Figure b). In both groups, PV isolation was performed sequentially for the left superior PV (LSPV), left inferior PV (LIPV), right superior PV (RSPV), and right inferior PV (RIPV). Results The external pre-application group exhibited significantly fewer MESs during PV ablation, except for the RSPV (LSPV: 201 ± 105 vs. 112 ± 61, P=0.002; LIPV: 125 ± 63 vs. 58 ± 42, P<0.001; RSPV: 70 ± 64 vs. 34 ± 23, P=0.03). In both groups, MES counts were highest for the LSPV (conventional group: P<0.001; external pre-application group: P<0.001) (Figure c). There was no significant difference in the incidence of postoperative asymptomatic silent cerebral lesions between the groups (35%, P=1.00). Conclusion The external pre-application technique was associated with a reduction in MESs during initial PV isolation using the PulseSelect system.