PFA has been a game-changer for heart patients—but there are still risks
Pulsed field ablation (PFA) has been embraced by electrophysiologists due to its improved safety profile over thermal ablation. However, PFA still comes with its own set of safety concerns clinicians should know about as they start using the technology on a regular basis.
Devi Nair, MD, director of electrophysiology and research at St. Bernards Medical Center, spoke with Cardiovascular Business at Heart Rhythm 2026 about PFA for an exclusive video interview. She highlighted the massive impact it has already had on patient care.
“I think PFA has been a paradigm shift for us in the ablation space,” Nair said.
Unlike radiofrequency or cryoablation, which rely on thermal energy to destroy tissue, PFA uses electrical fields to more selectively ablate cardiac tissue. The technology has gained widespread enthusiasm because of the increased safety to nearby structures. Nair said EPs want to use whatever technology edge they can to prevent rare, but serious complications.
“We are seeing a great amount of safety,” Nair explained. “We’re not seeing phrenic nerve issues. We’re not seeing issues with the esophagus. We’re not seeing a lot of collateral damage. So the safety aspect is what I think has kind of driven this whole adoption.”
The technology has rapidly diversified, with multiple catheter designs now entering the market. Nair highlighted several systems currently in use or recently approved, including Medtronic’s PulseSelect, Boston Scientific’s Farapulse, Johnson & Johnson MedTech’s variable-loop VariPulse catheter, Kardium’s 120-electrode Globe array catheter, and the Sphere-9 catheter, which she noted is currently the only FDA-approved medium-footprint PFA catheter.
While efficacy across investigational device exemption (IDE) trials has generally been non-inferior to thermal strategies, Nair said physicians are also attracted to the ease of use offered by larger-footprint catheter designs.
New complications caused by PFA energy
As adoption has expanded into real-world practice, clinicians began to identify complications unique to PFA therapy. Coronary artery spasm has emerged as a key concern, for example.
“Proximity-related spasm where you are near a blood vessel, you deliver pulsed field energy, and it’s been shown that causes spasm in the arteries,” Nair said.
To counteract this issue, many operators now administer nitroglycerin prophylactically during procedures performed near coronary vessels. However, Nair said a more troubling phenomenon is the emergence of generalized coronary spasm occurring even when ablation is not performed near an artery.
“What’s bothersome is the idea of generalized spasm where you’re not even in the proximity of an artery and then you’re getting spasm and you’re getting ventricular arrhythmias, and you can even have sudden death,” she explained.
Although the complication rate remains very low, below 1%, Nair said reports from the MANIFEST-US registry and other studies have heightened awareness across the electrophysiology community.
Nair also described findings from research involving the Marshallese population, where investigators observed an unexpectedly very high rate of PFA-induced vasospasm of nearly 100%.
“We don’t understand this as well. We are still trying to figure out, what are the genetics? Maybe there’s something to do with the ethnic backgrounds. Maybe it’s got to do with the technology,” she said.
Nair emphasized that the phenomenon does not appear isolated to any single PFA platform.
“There is a TRACE-AF registry that’s coming together among multiple operators around the globe looking specifically at these fatal and malignant cardiac arrhythmias that are happening post-PFA,” Nair added.
PFA hemolysis linked to catheter design and blood exposure
Another emerging issue is hemolysis, or destruction of red blood cells. This might occur when pulse field energy is inadvertently delivered into circulating blood rather than directly into tissue. Several operators at Heart Rhythm said this may be caused when part of the PFA catheter is floating in the blood pool rather than contacting cardiac tissue. Nair said catheter design plays a major role in this risk.
“There are catheters where you can have part of the electrodes kind of floating in the atrium while you’re delivering, whereas half might be touching,” she explained. “There are catheters that only deliver the energy very focused towards the tissue and don’t disperse that energy away from the tissue.”
Nair pointed to systems such as the Globe catheter and Abbott's Volt balloon-basket catheter as examples of designs intended to direct energy more specifically toward tissue surfaces. The Medtronic Sphere-9 catheter, with its smaller footprint, has also demonstrated less hemolysis so far.
To minimize this complication risk, operators are increasingly relying on intracardiac echocardiography (ICE), advanced mapping systems and improved catheter-tissue contact visualization.
“What we understood is that we need contact,” Nair said. “That’s what’s important to prevent or minimize hemolysis.”
In cases where extensive ablation is anticipated, she said physicians may also pre-hydrate patients to reduce complications associated with hemolysis.
Despite the emerging safety concerns, Nair emphasized that PFA remains a major advancement for AFib treatment. Ongoing data collection will help refine procedural safety as adoption continues worldwide.
Dave Fornell has covered healthcare for more than 17 years, with a focus in cardiology and radiology. Fornell is a 5-time winner of a Jesse H. Neal Award, the most prestigious editorial honors in the field of specialized journalism. The wins included best technical content, best use of social media and best COVID-19 coverage. Fornell was also a three-time Neal finalist for best range of work by a single author. He produces more than 100 editorial videos each year, most of them interviews with key opinion leaders in medicine. He also writes technical articles, covers key trends, conducts video hospital site visits, and is very involved with social media. E-mail: [email protected]