Pulsed field ablation (PFA) was shown to be effective in treating patients with paroxysmal atrial fibrillation (AFib), with more patients free from atrial arrhythmias (AA) when compared with patients treated with thermal ablation, according to results from a secondary analysis of the ADVENT trial. The results of the single-blind study were presented at Heart Rhythm 2024 and simultaneously published in JACC.

PFA resulted in significantly more patients with a post-ablation residual AA burden below the clinically meaningful threshold of 0.1% compared to thermal ablation (odds ratio [OR], 1.5; p=0.04), according to primary investigator Vivek Y. Reddy, MD, and colleagues. In addition, patients treated using PFA had a lower risk of esophageal or phrenic nerve injury than patients treated with thermal ablation.

In the analysis, data were examined from 299 patients who underwent PFA and 294 who underwent thermal ablation. Results showed that an AA burden >0.01% was associated with a significantly reduced quality of life and increase in clinical interventions (re-do ablation, cardioversion, hospitalization). Examining outcomes by baseline demographics showed there was less residual AA in patients with prior failed class I/III antiarrhythmic drugs after PFA vs. thermal ablation (OR, 2.5; p=0.02).

In an accompanying editorial comment, Peter Hanna, MD, PhD, et al., write: "Using AA burden as an endpoint in ablation trials may prompt a reframing of goals, from cure to successful management of AF," wrote investigators. "As we shift from the objective of curing [AFib] to managing [AFib], use of continuous monitoring will help to identify the burden of [AFib] that is as low as reasonably achievable."

A substudy of ADVENT, also presented at the meeting and simultaneously published in JACC: Clinical Electrophysiology, examined whether autonomic denervation is less pronounced with the use of PFA vs. thermal ablation, which would give patients with paroxysmal AFib greater long-term freedom from AFib.

ADVENT started with 607 patients randomly assigned to be treated using PFA or thermal ablation. Because some patients exited the study before 12 months or missed follow-up 72-hour Holter monitors, the subanalysis looked at the data of the remaining 379 patients. Of those patients, 194 were treated with PFA and 185 thermal ablation who completed six- and 12-month Holter monitoring.

Results showed that compared to PFA, patients who had thermal ablation had significantly greater increases in heart rate from baseline to six and 12 months, and heart rate variability were significantly lower at both time points.

The authors concluded that:

• Autonomic effects were more pronounced after thermal ablation compared to PFA.
• The effects of thermal ablation on autonomic modulation persist at one year after ablation.
• Both radiofrequency and cryoballoon ablation had a similar effect on autonomic modulation.
• Patients had more bradycardic events after PFA compared to thermal ablation. These findings have important implications for the energy modality used to treat AFib.

"Freedom from [AFib] is the same after PFA and thermal ablation, arguing that autonomic effects are not additive to [pulmonary vein] isolation. Bradycardic events are more common after PFA compared to thermal ablation; whether patients with tachy-brady syndrome and [AFib] may benefit from thermal ablation requires further study," concluded the subanalysis investigators, led by Edward P. Gerstenfeld, MD. MS, FACC.

Clinical Topics: Arrhythmias and Clinical EP, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias

Keywords: Atrial Fibrillation, Electrophysiology

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