Impact of pulsed field ablation dose and contact force on atrial lesion transmurality and contiguity: prospective evaluation in a porcine beating heart model
J Marazzato, F Zhou, T Sprangler, P Parikh, H Nakagawa, D Nair, S Mohanty, V M La Fazia, M Schiavone, M V Tritto, A Natale, X Zhang, L Di BiaseAbstract
Introduction
Pulsed-field ablation (PFA), is a non-thermal energy source widely used in interventional cardiac electrophysiology. Although electroporation is highly selective for myocardial tissue, it is not known which ablation parameters allow for the creation of effective and long-lasting lesions during PFA.
Purpose
In this study, we sought to evaluate which PFA settings are associated with chronic effective atrial lesions in swine undergoing PFA with the OMNYPULSE ablation catheter.
Methods
Twelve pigs were equally sorted into 2 groups according to the PFA dose: x6 (group A) vs. x12 applications per ablation (Group B). Three-dimensional mapping of the atria (CARTO) was followed by PFA at the right superior (RSPV) and right inferior pulmonary veins (RIPV), cavotricuspid isthmus (CTI), right atrial prosterior wall (RAPW), left atrial (LA) roof, and mitral annulus (MA). Chronic lesion transmurality and contiguity were assessed on 30-day histology. Transmurality was defined as >80% fibrotic replacement of the whole myocardial thickness post ablation in at least one histology sample. Lesion contiguity was defined as the absence of gaps for more than 75% of the lesion length at any site.
Results
The procedure proved to be safe and effective. No periprocedural complications occurred in either of the two groups analyzed. Contact force values displayed no differences between the two groups (Group A: 29 ± 15 g vs. Group B: 29 ± 15 g). At 30-day histological evaluation, transmural and contiguous lesions were observed at the RPVs (100%) regardless of the electroporation dose used. In contrast, non-transmural lesions were observed at the MA (16.7–20%) and LA roof (0–20%) despite the presence of deep lesions in these anatomical regions. Finally, the PFA dose was found to be decisive in obtaining deep, contiguous, and transmural lesions at the other sites investigated, namely the CTI (Group A: 83% and Group B: 100%) and the RAPW (Group A: 83% and Group B: 100%).
Conclusions
PFA ablation with OMNYPULSE proved feasible, however, different atrial sites require specific PFA settings to achieve lesion transmurality and contiguity. Further studies are required to identify the optimal PFA parameters to achieve effective lesions in this setting.