Procedural characteristics, details on epicardial mapping-based lesion transmurality, and long-term success of posterior wall isolation with a pentaspline pulsed field ablation device
Authors: Della Rocca D , Cespon-Fernandez M , Glowniak A , Sousonis V , Vetta G , Magnocavallo M , Pannone L , Sorgente A , Mene R , Del Monte A , Sarkozy A , Boveda S , Natale A , De Asmundis C , Chierchia G B 
Published: May 2024

Abstract

Background
Achieving durable posterior wall isolation (PWI) with thermal-based energies is challenging, as reconnection rates have been reported to be up to 60%. Additionally, PWI can significantly increase the risk of collateral thermal damage to the esophagus. Pulsed field ablation (PFA) is a non-thermal energy source with a remarkable safety profile due to its selectivity to cardiac tissue. Additionally, PWI durability was reported to be 100% in a recent phase-3 study enrolling persistent AF patients undergoing PFA via the FarapulseTM system.

Purpose
To report procedural details, acute lesion transmurality, and long-term success of PWI via the FarapulseTMsystem.

Methods
Consecutive persistent AF patients undergoing first-time ablation with the FarapulseTM system at four different centres were prospectively enrolled. All patients received first-time pulmonary vein isolation (PVI) and PWI. PFA was performed with either a 31mm or a 35mm device and an energy output of 2.0kV. At least 2 applications per position were delivered. Primary efficacy endpoint was freedom from any atrial tachyarrhythmia &gt;30s after a 3month blanking period.
PW lesion transmurality was assessed in a subpopulation of patients with an indication for hybrid AF ablation and left atrial appendage (LAA) clipping. The procedure was performed according to the following steps: 1) endocardial PVI plus PWI via the FarapulseTM system; 2) endocardial high-density mapping with RhythmiaTM plus Intellanav OrionTM; 3) thoracoscopy-assisted epicardial high-density mapping with Intellanav OrionTM 4) left atrial appendage clipping.

Results
157 persistent AF patients (mean age: 62±11years; 75.5% males) were included.
First-pass PVI was achieved in 100% of patients. On average, pulsed electric field applications for PWI were 16.3±2.4. Mean procedural time was 66±17min; left atrial dwelling and fluoroscopy times were 46±12min and 14±6min, respectively. SR restoration during PWI was observed in 8 (5.1%) cases. Minor and major periprocedural complications occurred in 2.5% (groin hematoma: 4pts) and 0.6% (diplopia with negative cerebral MRI) patients, respectively.
During a mean follow-up of 353±58 days, arrhythmia-free survival was 78.3% (n=123). A redo ablation was performed in 23 patients, showing reconnection of 22.8% of PVs. Durable PWI was observed in 82.6% of patients.
In the subpopulation of patients (n=3) undergoing hybrid ablation plus LAA clipping, thoracoscopy-guided epicardial mapping of the PW was performed between 57 and 72 minutes after the last endocardial PFA application. All patients showed transmural PWI (Figure1).

Conclusions
In a real-world multicenter registry, PWI by means of the FarapulseTM system was safe and feasible, contributing to approximately 80% success rate after 1 year. Endocardial PFA-based PWI led to 100% transmural lesions acutely, with a rate of reconnection &lt;20% at redo procedures.