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.