Pulsed-field or thermal ablation, which is better for treating paroxysmal atrial fibrillation?

USA: The ADVENT trial showed pulsed field catheter ablation to be noninferior to thermal ablation with respect to safety and efficacy among patients with symptomatic paroxysmal atrial fibrillation (AF) who have failed prior AAD (antiarrhythmic drug) therapy. 

The trial findings, presented at the European Society of Cardiology Congress 2023 and simultaneously published in the New England Journal of Medicine, demonstrated the potential of pulsed-field ablation (PFA) as a viable treatment option for patients with paroxysmal AF. 

The ADVENT trial, the first of its kind, compared the outcomes of PFA with conventional radiofrequency and cryoballoon ablation techniques. 

Conducted by experienced operators in thermal ablation techniques, the Farapulse system from Boston Scientific showcased noninferior efficacy and safety outcomes over a one-year follow-up period. Dr. Vivek Reddy of the Icahn School of Medicine at Mount Sinai, New York, reported that PFA provided compelling results, including less pulmonary vein narrowing compared to conventional methods. This reduction in pulmonary vein narrowing was associated with shorter total procedure and ablation times, though fluoroscopy time was longer with PFA. 

Dr. Reddy expressed excitement about PFA as a new technology with potential safety benefits, including a reduced risk of complications such as atrioesophageal fistula. Additionally, PFA demonstrated comparable efficacy to existing methods. Notably, PFA's unique advantage lies in its specificity to the myocardial tissue, potentially minimizing collateral damage that can occur with thermal ablation technologies.

The ADVENT trial involved 607 patients aged 75 or younger who had paroxysmal AF and had not responded to at least one class I-IV antiarrhythmic drug. The study found that PFA's acute success rate for pulmonary vein isolation was on par with thermal ablation methods, but with significantly more efficient procedure times. While fluoroscopy time was extended in the PFA group, the incorporation of nonfluoroscopic electroanatomical mapping systems could potentially mitigate this drawback.

The primary efficacy endpoint was met by 73.3% of patients in the PFA arm and 71.3% of patients in the control arm, demonstrating noninferiority. Safety outcomes were also favourable, with low rates of device- and procedure-related serious adverse events in both groups. Dr. Reddy dismissed a single death during the trial as an anomaly rather than indicative of risks associated with PFA.

While the results were seen as promising, Dr. Samuel Kiil Sørensen of Gentofte Hospital, Copenhagen, emphasized that the durability of PFA ablations was an important consideration, with initial studies indicating a high rate of recurrent pulmonary vein conduction. Dr. Sørensen also noted that as first-generation technology, PFA's full potential might not yet be realised. The ADVENT trial is anticipated to support the regulatory approval of the Farapulse system in the United States.

As the medical community awaits further research and potential approvals, PFA's novel approach to treating paroxysmal atrial fibrillation has generated considerable interest and optimism. The technology's potential to combine efficacy and safety with shorter procedure times could offer a new dimension in the landscape of AF ablation treatments.

Reference:

Reddy VY, Gerstenfeld EP, Natale A, et al. Pulsed field or conventional thermal ablation for paroxysmal atrial fibrillation. N Engl J Med. 2023;Epub ahead of print.