Analysis: Pulsed Field Afib Ablation Superior to Thermal Methods (2024)

— Also, what real-world data are showing about new workflow patterns and PFA use in heart failure

by Crystal Phend , Contributing Editor, MedPage Today May 21, 2024

BOSTON -- Pulsed field ablation (PFA) trials continued to accrue positive data, as reported at the Heart Rhythm Society (HRS) annual meeting.

Superiority, Finally

Secondary analysis of the pivotal ADVENT trial showed that PFA with the Farawave device was actually superior in one respect to conventional thermal ablation for paroxysmal atrial fibrillation (Afib) in that first randomized head-to-head trial.

While the main trial had shown noninferiority for efficacy at 1 year in freedom from atrial arrhythmias, post hoc analysis of the atrial arrhythmia burden calculated from transtelephonic ECG and Holter monitoring showed more patients achieved less than 0.1% residual burden with PFA than with thermal ablation (82% vs 75%, OR 1.5, P=0.04).

That amount of burden would be the equivalent of 8.6 minutes of atrial arrhythmia across two 72-hour Holter monitoring periods, or about 1.4 minutes of arrhythmia per day, said presenter Vivek Reddy, MD, of the Mount Sinai Fuster Heart Hospital and Icahn School of Medicine at Mount Sinai in New York City. The findings were also published in the Journal of the American College of Cardiology.

"Historically and in ADVENT, the binary endpoint of 30 seconds of arrhythmia has been used to define success or failure. And this is an arbitrary endpoint, which I think most people agree doesn't have significant clinical significance," he said.

Pooling the data across the two treatment groups, an atrial arrhythmia burden of more than 0.1% was associated with lower quality of life scores and higher likelihood of redo ablation, cardioversion and hospitalization -- supporting its clinical relevance as an endpoint.

To calculate post-blanking period atrial arrhythmia burden without having implantable devices, the researchers divided the total amount of time the patients spent in atrial fibrillation by the total amount of time available on Holter monitoring and transtelephonic ECG monitoring. Quality of life assessments were performed at baseline and at 12 months.

However, atrial arrhythmia burden was developed based on continuous monitoring, cautioned session study discussant Michael Glikson, MD, of Shaare Zedek Medical Center in Jerusalem. "The extrapolation from continuous to intermittent monitoring is imperfect, especially with partial compliance, as we've seen here."

Nevertheless, he concluded: "This is the first demonstration of pulsed field ablation advantage over thermal using atrial burden data. Atrial burden has been established as a better measure of ablation success than a single short episode of recurrence. Atrial burden should be the preferred monitoring endpoint in future studies."

Real-World Results

Lucas Boersma, MD, PhD, of St. Antonius Hospital in Nieuwegein, The Netherlands, reported on 30-day data from the FARADISE global registry of real-world use of the Farapulse pentaspline PFA catheter in 1,173 patients across Europe, Asia, Australia, and the Middle East. Afib was paroxysmal in 65% of cases.

Safety showed device or procedure related serious adverse events in 4.0%, most often minor vascular access complications (2.3%) followed by major vascular complications (0.9%). There were no reported deaths or instances of coronary spasm, persistent phrenic nerve palsy, atrioesophageal fistula, pulmonary vein stenosis, or esophageal lesions.

Hemolysis was uncommon (0.1%), but one case resulted in renal failure. All cases occurred in the top quartile of number of PFA applications and three of four occurred in persistent Afib patients. Immediate post-procedure fluid infusion might help prevent this complication, Boersma noted.

Follow-up for up to 3 years is planned.

HRS session study discussant Kevin Jackson, MD, of Duke University Medical Center in Durham, North Carolina, noted that these safety findings were "quite comparable" to what was expected from the pivotal study data.

While reassuring for safety, the surprises came from workflow findings, he noted. He pointed to the 59% of patients treated under general anesthesia versus 37% under deep sedation and 85% done without a mapping system. And, he added, fluoroscopy times are likely to go up with PFA, even after significant experience (11 min for pulmonary vein isolation [PVI], 16 min for PVI+ after more than 50 cases).

"This would be a major departure to how cases are done in some areas," Jackson noted.

Use in Heart Failure

While guidelines recommend catheter ablation as a primary approach for managing Afib only for heart failure with reduced ejection fraction (HFrEF), analysis of the MANIFEST-PF registry suggested benefits across the ejection fraction spectrum in heart failure (HF).

In the multicenter patient-level registry of consecutive patients undergoing PFA for paroxysmal or persistent Afib, 1-year freedom from atrial arrhythmia was significantly higher in patients without HF than in those with HF with preserved ejection fraction or HF with moderately reduced or reduced ejection fraction (no HF 79.9%, HFpEF 71.3%, and HFmrEF or HFrEF 67.5%, respectively, P<0.001). However, HFpEF patients didn't get significantly less benefit than the HFmrEF/HFrEF patients (P=0.26).

That was true in both paroxysmal and persistent Afib, reported Mohit Turagam, MD, of Icahn School of Medicine at Mount Sinai in New York City. Major adverse event rates were likewise similar between groups in the findings, which were also published in JACC: Clinical Electrophysiology.

"I think the data is very clear. It's non-randomized, but it seems to be quite safe," added Reddy, who was a co-author. "But it doesn't really include patients who have very significant heart failure. So I think that is an important notation."