Cerebral Safety of Two Pulsed Field Ablation Workflows for Pulmonary Vein Isolation: Results From the Randomized TWOSOME MRI Study

BACKGROUND: Data on silent cerebral events/lesions (SCE/SCL) following pulsed field ablation (PFA) for pulmonary vein isolation (PVI) are limited. This study aimed to assess the incidence of SCE/SCL using cerebral magnetic resonance imaging (cMRI) in atrial fibrillation (AF) patients undergoing PVI with two distinct PFA systems and workflows. METHODS: In this prospective, single-center TWOSOME MRI substudy, patients with paroxysmal AF were randomized 1:1 to single-shot or single-tip PFA. Single-shot PVI was performed using a pentaspline PFA catheter (single-transseptal access, PV-angiography, no 3D mapping) and single-tip PVI using a PFA generator with a focal ablation catheter (double-transseptal access, 3D mapping). A predefined consecutive cohort underwent 1.5-T cMRI 24 h after the procedure. SCE were defined as acute cMRI-detected lesions resolving on 6-week follow-up cMRI, and SCL as persistent lesions. Baseline characteristics, neurological symptoms, procedural data, and cMRI findings were assessed. RESULTS: Fifty patients underwent cMRI (25 per group). Acute SCE were detected in 3/50 patients (6%; 95% CI 1.3-16.5), with 1/25 (4%) in the single-shot group and 2/25 (8%) in the single-tip group (p = 1.00). All SCE resolved on follow-up imaging, with no evidence of persistent SCL. One symptomatic stroke occurred in the single-shot group, unrelated to PFA, and was attributed to air embolization during transseptal puncture. No permanent neurological deficits occurred. CONCLUSIONS: In this exploratory cMRI study, both PFA workflows showed a low incidence of SCE without evidence of SCL or PFA-related neurological complications. Larger studies are required to compare cerebral safety profiles of PFA technologies. TRIAL REGISTRATION: NCT07175727 (clinicaltrials.gov).