PULSED AF Trial Evaluates New Ablation Technology to Treat AFib

March 6, 2023—The American College of Cardiology (ACC) announced that results from the prospective PULSED AF global clinical trial of the use of pulsed field ablation to treat atrial fibrillation (AFib) demonstrated that the new technology was successful at eliminating episodes of abnormal heart rhythms for 12 months in up to two-thirds of patients.

The findings were presented by Atul Verma, MD, at ACC.23/WCC, the ACC’s annual scientific session together with the World Congress of Cardiology held March 4-6, 2023, in New Orleans, Louisiana. Simultaneously, “Pulsed Field Ablation for the Treatment of Atrial Fibrillation: PULSED AF Pivotal Trial” was published by Dr. Verma et al online in Circulation. The PULSED AF study was funded by Medtronic.

According to ACC, pulsed field ablation is different from thermal ablation—which has been the standard ablation approach for AFib for decades—in that it disables cardiac cells using electricity rather than extreme temperatures. The investigators advised that the technology allows ablation procedures to be performed in less time and with a lower risk of damage to surrounding tissues than thermal ablation.

In pulsed field ablation, electrical fields create tiny holes in the membranes of heart muscle cells, which causes the targeted cells that contribute to irregular heart rhythms to die without altering the overall structure of the tissue or affecting other cell types. For approximately a decade, pulsed field ablation has been used to treat cancer by killing tumor cells. Recently, the technology has been applied to the heart.

Dr. Verma, who is head of cardiology at McGill University Health Center in Montreal, Canada, commented in the ACC press release, “The efficacy of the procedure is similar to what we see in thermal ablation, but we’re getting it much faster and with much more safety. That is a major development for the field of electrophysiology.”

As summarized in the ACC press release, the PULSED AF study was conducted at 41 sites in nine countries (the United States, Canada, Australia, Austria, Belgium, France, Japan, the Netherlands, and Spain) and enrolled patients who continued to experience AFib despite taking medicines to improve heart rhythm regulation.

In the trial, each physician investigator first treated one patient to gain experience with the technique, for a total of 60 patients. Then, they continued to enroll patients and perform pulsed field ablations up to an additional 300 procedures among all sites and final outcomes from these 300 procedures were analyzed. Half of the patients had paroxysmal AFib, and half had persistent AFib.

For the trial’s primary endpoint, 66% of patients with paroxysmal AFib and 55% of patients with persistent AFib experienced no AFib episodes between 3 and 12 months after the procedure, as measured by weekly and symptomatic self-reports, electrocardiograms, and 24-hour Holter monitoring. These rates of efficacy are on par with outcomes from thermal ablation procedures, advised the investigators in the ACC press release.

In addition, all patients reported significant and meaningful improvements in quality of life and there was one adverse event in each of the two patient cohorts, for an adverse event rate of 0.7%.

Most pulsed field ablation procedures were completed in less than 1 hour, making them substantially faster than thermal ablation procedures, which typically take 2 hours or more, noted the investigators in the ACC press release.

“There’s been a huge amount of enthusiasm over this technology in the electrophysiology community,” stated Dr. Verma in the ACC press release. “Many physicians feel that pulsed field ablation will become the dominant way of doing ablation moving forward, so in that sense, it’s really a paradigm shift.”

The trial was limited by its lack of a control group. In addition, larger studies will be needed to provide more definitive evidence of the procedure’s safety since adverse events are generally rare with cardiac ablation. The success rates and safety of pulsed field ablation could improve further as the technology continues to advance, stated the investigators in the ACC press release.