Silent cerebral infarctions following pulsed-field ablation using FARAPULSE and PulseSelect

Background Pulsed-field ablation (PFA) for atrial fibrillation (AF) has emerged as a safer modality than conventional thermal ablation. Concurrently, cerebral infarctions (CIs) after PFA have been sporadically reported, most of which are asymptomatic. Although their mechanisms remain unclear, air embolism is considered as a main cause due to air-trapping by the sheaths with larger diameter and the various structure shapes of the PFA. Meanwhile, these procedural characteristics may also become potential risks for thrombus formation. Purpose We investigated the occurrence and predictors of CIs following PFA. Methods A total of 56 patients with AF referred for PFA were enrolled (FARAPULSE, n=32; PulseSelect, n=24). Preoperative anticoagulation was managed with dabigatran bridging or warfarin continuation, and the absence of left atrial appendage thrombus was confirmed within one week by contrast-enhanced computed tomography or transesophageal echocardiography in all patients. The left atrium mapping was performed before and after PFA using high density mapping catheter. Concerning brain magnetic resonance imaging (MRI) on the following day, CIs were defined as high-signal-intensity lesions on diffusion-weighted imaging and air embolism as low-signal-intensity lesions on T2*-weighted imaging(T2*WI) or susceptibility-weighted imaging (SWI). Results CIs were detected in total 22 patients (39.3%) {10 patients(31.3%) in FARAPULSE and 12 patients (50.0%) in PulseSelect). No patients exhibited neurological symptoms. The median lesion number of CIs per patient was 1(1-3) in FARAPULSE and 1(1-2) in PulseSelect. Regarding MRI findings, no CI lesions showed low intensity on T2*WI or SWI (figure1). In univariate analysis, CI occurrence related to higher brain natriuretic peptide before the PFA (143.4[38.1-302.7] vs. 58.7[28.6-108.2]pg/mL, p=0.019), the use of EnSite mapping system (77% vs. 47%, p=0.03) and lower minimum activated clotting time (ACT) during the procedure (364[352-390] vs. 396[363-423] seconds, p=0.029). Multivariate analysis revealed lower minimum ACT (odds ratio[OR]: 0.981, p=0.048) as the only predictors of CI occurrence. The cut-off value of minimum ACT was 420 seconds with 100% sensitivity and 29.4% specificity (figure2). Conclusion In PFA using FARAPULSE and PulseSelect, CIs were likely to occur under insufficient ACT control. Additionally, no patients showed typical air embolism by MRI findings, and which also support the result of ACT. It might be better to keep ACT level above 420 seconds during the PFA procedure for preventing silent CIs.