In April, we reported on a study that raised alarms for safety issues with pulsed field ablation for atrial fibrillation. In this report, we follow up on subsequent developments for this technology.
Pulsed field ablation (PFA) has been embraced as a catheter ablation modality with potential to be safer for atrial fibrillation (Afib, or AF) treatment due to its tissue-selective mechanism of cell death. Nevertheless, growing evidence ties first-generation devices to complications of their own, driving anticipation for newer devices in development.
In the NEMESIS-PFA registry study presented at the Heart Rhythm Society annual meeting in April, researchers showed that real-world PFA -- most often using the Farawave pentaspline device -- was associated with more markers of non-target myocardial injury, hemolysis, acute kidney injury, and global cardiac dysfunction compared with conventional radiofrequency ablation.
"Whereas early preclinical and clinical studies positioned PFA as a safer alternative to thermal ablation due to its tissue selectivity, our findings challenge prevailing assumptions about PFA's safety profile and help reshape understanding of PFA's tissue effects," Dhanunjaya Lakkireddy, MD, of Kansas City Heart Rhythm Institute in Kansas, and colleagues reported in the spring.
Lakkireddy later pointed to the NEMESIS report's impact on practice.
"This brought out a significant alertness to the potential issues related to PFA. This led to aggressive and appropriate monitoring for hemolysis, appropriate hydration, and also watching for renal failure," he told MedPage Today in December.
The renal failure and other complications are obvious problems with these first-generation, large open-architecture, single-shot PFA catheters, according to Lakkireddy.
Two years ago, PFA technology entered the U.S. market with FDA approval of Medtronic's PulseSelect, a single-shot catheter with nine electrodes fixed on a loop for creating wide-area circumferential lesions on the pulmonary vein. Soon after, the second device to get FDA approval was Boston Scientific's Farapulse system (using the Farawave catheter), another single-shot system with configurable flower or basket shapes and 20 electrodes.
After approval in late 2024, Johnson & Johnson's Varipulse PFA system started 2025 on the wrong foot: Its early rollout had to be paused for about a month due to safety concerns, as four neurovascular events were reported over 130 cases across 14 sites and 40 operators.
The company later said the devices operate as intended and put the blame on a high number of ablations, the stacking of ablations, and/or ablations outside of the pulmonary veins delivered by operators. Varipulse's commercial use was then allowed to resume with updated instructions for use to include enhanced guidance.
In September, the Globe system from Kardium gained FDA approval for PFA. That single-shot device comprises 122 electrodes in a spherical array design.
Yet more competitors are on the way.
"The next generation of catheters that are coming out seem to mitigate some of [the NEMESIS-reported] issues by changing the architecture as well as the biophysics of each individual catheter system," Lakkireddy said.
One example he cited is the Volt balloon-in-basket PFA system from Abbott. Volt's circumferential design, featuring eight electrode splines, is supposed to conform to anatomy and selectively deliver energy from only the electrodes in contact. Abbott boasted good 6-month safety and efficacy results from the VOLT-AF IDE study in paroxysmal and persistent Afib, and the device gained FDA approval for both forms of Afib in December.
"It is a good single-shot system with contained energy delivery with assured contact with the walls [and] no significant open bathing of blood during PFA application. This dramatically reduces the risk of hemolysis as well as extraneous unwanted myocardial injury while ensuring excellent contact with the tissue and delivery of energy," according to Lakkireddy.
Another promising candidate is the LotosPFA catheter/InRythm system from Insight Medtech, with its nanosecond pulsed energy expected to minimize nerve and skeletal muscle stimulation and obviate the need for general anesthesia.
In the InsightPFA trial, however, there was one LotosPFA patient who had evidence of hemolysis following extensive ablation, albeit without acute renal impairment and recovering spontaneously within 24 hours. "This event was likely attributable to the higher number of pulse applications (108 applications), consistent with established evidence linking hemolysis to insufficient tissue contact and excessive energy delivery," the study authors wrote.
"This technology is part of the explosion of PFA ablation technologies that continue to penetrate the AF ablation landscape," wrote Rahul Doshi, MD, of Arizona State University in Scottsdale, in an editorial.
The enthusiasm for PFA was evident in a survey released in 2024 that predicted that this technology will account for nearly half of all Afib procedures in 2025.
"What waits to be seen is whether increased competition will drive down the costs of these technologies and allow for even more widespread adoption, including in the ASC [ambulatory surgical center]," according to Doshi. "This then could lead to more widespread access to this therapy for the general population, which could have a dramatic impact on this disease that is of pandemic proportion."
Indeed, in November, CMS officially added catheter ablation for arrhythmia to the list of ASC-covered procedures, green-lighting a shift in volume from the traditional hospital setting.
Disclosures
Lakkireddy has disclosed consulting for Abbott, Atricure, Biosense Webster, Medtronic, and Johnson & Johnson.
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