Introduction:
Pulmonary vein isolation (PVI) remains one of the most effective treatment strategies for atrial fibrillation1. Thermal ablation technologies like radiofrequency (RF) and cryoablation (Cryo) rely on direct contact to effectively transfer energy to produce irreversible thermal damage to cardiac tissue and durable PVI2–4. After being introduced in oncology over 30 years ago5,6, pulsed electric field (PEF) ablation has been developed as a primarily non-thermal modality for cardiac tissue ablation, achieved by applying short duration bursts of high voltage electric fields. Cardiac myocytes within a critical voltage gradient area undergo cell death due to destabilization of the cell equilibrium7.
PEF ablation treatment size is dependent on several factors, including waveform characteristics, electrode configuration, and field interaction with target tissues7. Although it has been proposed that, unlike thermal modalities, PEF ablation may not be dependent on catheter-tissue contact (CTC) because of its field-based nature8, computational modeling data and ex vivo bench studies using a bipolar PEF system have demonstrated a profound treatment size dependence on catheter-tissue proximity9. Proximity and contact dependence for PEF ablation, however, has not been thoroughly examined in vivo .
We investigated the relationship between CTC and monopolar PEF ablation in a preclinical porcine model. This study sought to determine, 1) if CTC is necessary for effective PEF treatment, and 2) how CTC can be used to optimize PEF ablation workflows and efficacy.