First-in-human trial of atrial fibrillation ablation using real time tissue optical assessment to predict pulsed field lesion durability

Loss of bipolar electrograms immediately after pulsed field ablation (PFA) makes lesion durability assessment challenging. The aim of this trial (NCT06700226) was to evaluate a novel ablation system that can optically predict lesion durability by detecting structural changes in the tissue during ablation. Patients with paroxysmal atrial fibrillation underwent pulmonary vein isolation (PVI) using PFA (AblaView®, MedLumics). Using polarization sensitive optical coherence reflectometry (PS-OCR), reflective characteristics of myocardial tissue and visualization of real-time contrast between healthy tissue and ablated tissue using a drop in tissue birefringence (BiR) was assessed. Wide antral PVI was performed using single point irrigated PFA (unipolar, 1800V, 3 trains, 21sec). Remapping was performed at 3 months. Primary efficacy outcome was the ability of PS-OCR to predict lesion durability at 3-month remapping. Serious adverse events were recorded. Ten patients were included. In total, 38/40 PVs could be isolated with the system. The mean drop of BiR was 17.3±11.5%. Dragging across the ablation lines showed a persistent drop in BiR. During the remap procedures (9/10 patients), 15 PVs (41.7%) were found to be electrically reconnected. The mean loss of BiR during the index ablation for durable lesions was 20.9%, while only 10.1% BiR loss was observed during the index ablation for reconnected areas (p<0.001). None of the points with ≥17% loss of birefringence was found to be reconnected. This first in human study supports the use of real-time drop in tissue BiR for lesion assessment during PFA delivery and its procedural safety.