Pulmonary vein narrowing after pulsed field versus thermal ablation

When it occurs, pulmonary vein (PV) stenosis after atrial fibrillation (AF) ablation is associated with significant morbidity. Even mild-to-moderate PV narrowing may have long-term implications. Unlike thermal ablation energies, such as radiofrequency (RF) or cryothermy, pulsed field ablation (PFA) is a non-thermal modality associated with less fibrotic proliferation. Herein, we compared the effects of PFA vs. thermal ablation on PV narrowing after AF ablation.

ADVENT was a multi-centre, randomized, single-blind study comparing PFA (pentaspline catheter) with thermal ablation—force-sensing RF or cryoballoon (CB)—to treat drug-refractory paroxysmal AF. Pulmonary vein diameter and aggregate cross-sectional area were obtained by baseline and 3-month imaging. The pre-specified, formally tested, secondary safety endpoint compared a measure of PV narrowing between PFA vs. thermal groups, with superiority defined by posterior probability > 0.975. Among subjects randomized to PFA (n = 305) or thermal ablation (n = 302), 259 PFA and 255 thermal ablation (137 RF and 118 CB) subjects had complete baseline and 3-month PV imaging. No subject had significant (≥70%) PV stenosis. Change in aggregate PV cross-sectional area was less with PFA (−0.9%) than thermal ablation (−12%, posterior probability > 0.999)—primarily driven by the RF sub-cohort (−19.5%) vs. CB sub-cohort (−3.3%). Almost half of all PFA PV diameters did not decrease, but the majority (80%) of RF PVs decreased, regardless of PV anatomic location.

In this first randomized comparison of PFA vs. thermal ablation, PFA resulted in less PV narrowing—thereby underscoring the qualitatively differential and favourable impact of PFA on PV tissue.