Pulsed-field ablation appears safe and effective for atrial fibrillation

Pulsed-field ablation (PFA) was found to be a successful and safe procedure for atrial fibrillation (AF) in the prospective, multicentre PULSED AF trial. At 12 months, both the paroxysmal and persistent AF cohorts met the predetermined effectiveness goals.

The risk of collateral tissue damage limits the use of thermal modes of ablation. PFA creates lesions non-thermally and within milliseconds through the mechanism of irreversible electroporation (IRE), explained study presenter Prof. Atul Verma (McGill University Health Centre, Canada) [1]. This involves exposing the tissue to high electric field gradients, inducing cell death through cell membrane hyper-permeabilisation.

The PULSED AF trial (NCT04198701) investigated PFA in patients with AF [2]. PULSED AF was designed as a prospective, global, non-randomised, paired single-arm trial in 41 centres in 9 countries. The 300 patients in the primary cohort had paroxysmal (n=150) or persistent (n=150) symptomatic AF resistant to class I and III antiarrhythmic drugs. They were all treated with PFA using the Medtronic PulseSelect PFA system. The primary effectiveness endpoint was freedom from a composite of acute procedural failure, arrhythmia recurrence, or antiarrhythmic escalation over 12 months, apart from the first 3 months post-procedure to allow for recovery.

Prof. Verma presented the acute and long-term outcomes of the trial [1]. Of the participants, 96% reached the 12-month follow-up. By that time, 66.2% (95% CI 57.9–73.2) of patients with paroxysmal AF and 55.1% (95% CI 46.7–62.7) of patients with persistent AF met the primary endpoint. In both groups, the pre-specified benchmark goal (50% and 40%, respectively) was beaten by a statistically significant margin. Prof. Verma put this result in perspective by saying: “This is at least as good as the results we would get from thermal ablation.” A more typical endpoint is the freedom from AF recurrence at 12 months, which was reached by 69.5% and 62.3% in the paroxysmal and persistent group, respectively. Freedom from symptomatic recurrence was achieved in about 80% of both groups.

The primary safety endpoint, freedom from a composite of serious procedure-related and device-related adverse events, occurred in 1 patient from each cohort (0.7%; 95% CI 0.1–4.6; P=0.002). “This is one of the lowest complication rates ever reported in a catheter-ablation trial anywhere,” according to Prof. Verma. PFA resulted in clinically meaningful improvements in quality of life. “The procedure time was very short,” added Prof. Verma, “despite this being a new procedure.”

The study was limited by the lack of a control group. Larger studies will have to demonstrate more definitive evidence of PFA's safety.

1. Verma A, et al. Pulsed field ablation treatment in paroxysmal and persistent atrial fibrillation patients: Acute and long-term outcomes from the PULSED AF Pivotal Trial. Session 409-08, ACC Scientific Session 2023, 4–6 March, New Orleans, USA.
2. Verma A, et al. Circulation. 2023 Mar 6. Doi: 10.1161/CIRCULATIONAHA.123.063988.

 

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Posted on 7 June 2023