Atrial fibrillation and flutter conversion with pulsed electric field delivery: preclinical proof of concept.

Introduction: Device-based therapies for treating atrial fibrillation (AF) episodes are limited. Using pulsed electric fields (PEF) to induce reversible electroporation of cardiac tissue may effectively terminate AF. Thus, we aimed to assess the feasibility of PEF delivery for converting atrial arrhythmias via reversible electroporation.

Methods and results: Four swine models were used in this acute study. Custom-made decapolar catheters for PEF delivery were deployed with the following configurations: (1) Endocardial right atrium (RA) and coronary sinus (CS), n = 2; and (2) Endocardial RA and epicardial left atrium (epiLA), n = 2. AF and atrial flutter (AFL) were induced with programmed stimulation. PEF delivery was performed using the BTX 830 generator. For each attempt, a single monophasic pulse at 10 or 20 µs pulse width was administered, with voltage varied across attempts (range 750-3000 V). Successful (type 1 and 2 breaks) and unsuccessful conversion attempts were recorded. Post-PEF signal changes and arrhythmias were identified. A total of 58 AF/AFL (28 and 30 respectively) episodes were induced. Of the 37 successful conversion attempts, 33 (89.1%) were type 1 breaks. Conversion success probabilities generally increased with higher voltages for both configurations. Greater than 70% conversion success was seen with ≥ 1500 V for the RA/CS configuration and ≥ 2000 V for the RA/epiLA configuration. Arrhythmias including intra-atrial delay and high-grade atrioventricular block were seen, usually following successive PEF deliveries. Significant muscle stimulation was provoked with the current experimental setup.

Conclusion: Termination of atrial arrhythmias with PEF delivery is feasible, although further work is required to optimize its efficacy and safety.