Pulsed Field Ablation May Bridge Gender Gap in AF Ablation

The clinical benefits and safety of pulsed field ablation (PFA) for atrial fibrillation (Afib) appeared to span both sexes in real-world practice, according to a postapproval registry from Europe.

Among people who underwent the Farapulse procedure in the MANIFEST-PF registry, the primary effectiveness outcome, 1-year freedom from atrial arrhythmia, was equally likely between men and women (79% vs 76.3%, P=0.28).

PFA’s clinical effectiveness was similarly higher for paroxysmal AF (~80%) than for persistent Afib/long-standing persistent Afib (~70%) between sexes, reported Vivek Reddy, MD, of Icahn School of Medicine at Mount Sinai in New York City, and colleagues.

Men and women also shared similar safety outcomes after PFA, both in terms of acute and chronic major adverse events. These events mostly consisted of cardiac tamponade (men 1.0% vs women 1.4%, P=0.46) and stroke (0.4% for both, P>0.99). There were no atrioesophageal fistulas or symptomatic pulmonary vein stenosis in either sex, Reddy’s group reported in JAMA Cardiology.

“The current data sets the stage for further studies using systematic, longer-term monitoring methods to confirm the effectiveness of PFA in male and female individuals,” the authors concluded.

PFA is a novel Afib ablation energy modality relying on high-voltage, ultrashort electric pulses unlike conventional thermal ablation with radiofrequency or cryoablation technology. Operators can take advantage of the fact that myocardial cells have the lowest thresholds to electric fields to preferentially ablate myocardial tissue, avoiding damage to adjacent phrenic nerve and esophageal structures.

This summer, the ADVENT trial report gave PFA noninferiority over thermal ablation in treating paroxysmal Afib.

“Although catheter ablation is the most effective rhythm control strategy for AF, it is associated with a significant learning curve and is not without the risk of complications. The recent emergence of PFA as a novel non-thermal technology has been met with great enthusiasm with early reports of high rates of durable single-procedure PVI [pulmonary vein isolation],” said Peter Kistler, MBBS, PhD, and Louise Segan, MBBS, MPH, both of Alfred Hospital and Baker Heart and Diabetes Institute in Melbourne, Australia, in an accompanying commentary.

Reddy and colleagues cited earlier first in-human PFA trials showing its effectiveness ranging from 55% to 92% at 1 year depending on Afib type, PFA technology used, and intensity of Afib monitoring.

Other Afib ablation technologies have shown patient sex as an additional factor in procedure success. This is thought to be due to inherent differences in the incidence, presentation, and management of Afib between men and women.

Women are expected to have more complex cases as they tend to present with older age, more comorbidities, smaller left atria and thinner atrial walls, and longer Afib duration due to delayed referral for catheter ablation. This group also has more nonparoxysmal Afib, more extensive atrial fibrosis, and a higher prevalence of non-pulmonary vein triggers, according to the study authors.

“Reassuringly, the MANIFEST-PF registry reports comparable success and safety for AF ablation between the sexes,” wrote Kistler and Segan. “This is a registry reporting the early experience with a new form of cardiac ablation, likely to undergo further refinements to the recipe and delivery of electroporation.”

The Farapulse PFA system became commercially available in Europe in 2021 before being acquired by Boston Scientific, which is now working on convincing the FDA to bring the technology to the U.S.

For their retrospective cohort study, Reddy and colleagues relied on the MANIFEST-PF registry to find 1,568 consecutive patients from March 2021 to May 2022 at 24 European centers.

The cohort had a mean age of 64.5 years and was 65% men. As expected, the minority of women tended to be older (mean 68 vs 62 years); however, they had more paroxysmal Afib (70.2% vs 62.4%) and fewer comorbidities such as coronary disease, heart failure, and sleep apnea.

Before Farapulse ablation, patients had to undergo imaging to rule out left atrial appendage thrombus.

All underwent first-ever PFA, delivered with the Farawave catheter, for paroxysmal or persistent Afib. Nearly all patients underwent pulmonary vein isolation. Additional ablation, performed at the operator’s discretion, reached 22.4% of women and 23.1% of men (P=0.79).

Clinical effectiveness was assessed with a median follow-up of 1 year including a median two 24-hour Holter monitors. The primary endpoint was freedom from clinically documented atrial arrhythmia for 30 seconds or longer after a 3-month blanking period.

Like this primary effectiveness endpoint, the secondary outcome of 1-year freedom from atrial arrhythmias without anti-arrhythmic drugs or repeated ablation also came out similar between sexes.

However, secondary clinical effectiveness was higher in men than women in the subset with paroxysmal Afib (75.7% vs 70.9%, P=0.04), while no such sex disparity was observed in persistent Afib/long-standing persistent Afib (66.8% vs 61.2%, P=0.59).

Kistler and Segan cautioned that the median of just two Holter monitors likely means that Afib recurrence was underestimated in the present report.

Study authors also acknowledged that they could not rule out treatment selection and unmeasured confounders playing a role in their results.

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