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

Background: Loss of bipolar electrograms immediately after pulsed field ablation (PFA) makes lesion durability assessment challenging.

Objective: 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.

Methods: 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.

Results: 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.

Conclusions: 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.