Rare Fatal Arrhythmias After PFA Highlighted in MAUDE Analysis

CHICAGO, IL—Though pulsed-field ablation (PFA) has lessened rates of certain rare but serious complications of ablation in patients with atrial fibrillation (AF), that may come at the cost of other infrequent issues, including fatal arrhythmic events, new data suggest.

Cardiac tamponade is the leading cause of death after ablation, with stroke coming in third, across different ablation types, according to a review of adverse event reports from the US Food and Drug Administration’s Manufacturer and User Facility Device Experience (MAUDE) database.

A discrepancy between technologies arose when looking at the second leading cause of death, which was esophageal complications for radiofrequency and cryoballoon systems and arrhythmic events for PFA, Roland Tilz, MD (University Hospital Schleswig-Holstein, Campus Lübeck, Germany), reported here at Heart Rhythm 2026.

He and his colleagues also estimated, based on MAUDE reports, manufacturer sales data, and findings from the EMBOL-AF study, that mortality rates—though very low overall—are about twice as high with PFA than with thermal ablation at 17.8 versus 8.6 per 100,000 procedures.

Tilz, who called himself a “PFA believer” at the start of his talk, indicated that he received some pushback about whether data like these should be discussed in an open forum.

“Of course, no one likes it, or many people don’t like it. It’s not good for industry, it’s not good for EPs,” he told TCTMD.

PFA has largely been touted as a much safer mode of ablation compared with radiofrequency or cryoballoon ablation, because it markedly lowers the risk of some of the more serious complications, including atrioesophageal fistula, phrenic nerve injury, and pulmonary vein stenosis.

“And all of a sudden, you get at least some data indicating that the safety profile is maybe not as good as we thought, and that there is a new complication,” Tilz said. “The problem is that with atrioesophageal fistula, we understood it’s related to energy delivered at the postererior wall, too much energy, and if it’s too close to the esophagus, this is a risk for the fistula.”

For the risks of vasospasm and sudden cardiac death tied to PFA, on the other hand, “we don’t understand it” or know how to prevent it, Tilz said.

Vivek Reddy, MD (Icahn School of Medicine at Mount Sinai, New York, NY), told TCTMD the idea that these types of data shouldn’t be discussed publicly is “ridiculous,” adding that “shining light on complications is critical. Everybody agrees with that.”

He cautioned, however, against relying on MAUDE reports to calculate the incidence of any adverse events, noting that the FDA explicitly states that this cannot be determined with the system.

More interesting, Reddy said, is the information on causes of death. For PFA, “this early arrhythmic issue is a real issue,” he said. He noted that the MANIFEST-US registry showed an overall mortality rate of 0.04% in patients treated with the Farapulse PFA system (Boston Scientific), which is a “very low rate.”

Still, Reddy said, “I think that it is important to look at real-world rates because now you’re going to start using it in sicker and sicker patients. There are different technologies. There’s learning curve issues, all of that. But you can’t do it with the MAUDE database. That’s my fundamental problem.”

The TiFFANY Study

When PFA was first introduced, “initially there was a great enthusiasm and it was thought to be super safe, but recently there have been a few publications indicating there might be some specific complications related to PFA and that it’s maybe not as safe as we thought initially,” Tilz said during his presentation, highlighting reports of phrenic nerve palsy, acute kidney injury, coronary artery spasm, and malignant arrhythmias.

In the current study, called TiFFANY, he and his colleagues focused on fatal adverse events after AF ablation recorded between 2014 and 2025 in the MAUDE database. Though MAUDE collects voluntary reports, there are also entities that are required to report adverse events, including manufacturers, importers, and device user facilities, Tilz pointed out. To estimate incidence of these events, the investigators also collected information from manufacturers on how many catheters they sold and from the EMBOL-AF study, with data on nearly 336,000 procedures performed at 204 centers in 56 countries, on procedure volumes.

The analysis included 399 reports of deaths in MAUDE and 28 cases identified through linked literature, bringing the total to 427 fatal events following ablation. Most of these reports (59.0%) came from the United States, with another 11.2% coming from Japan and 8.4% from France. The number of death reports increased over time.

Of those received since 2021, when the first death associated with PFA was recorded, 38.7% involved PFA, 36.0% radiofrequency ablation, and 25.3% cryoablation.

Among the reports in which cause of death was available, cardiac tamponade accounted for 37.8% and esophageal complications 25.7% when grouping all ablation technologies together.

With PFA, 16 patients died of arrhythmic events, mostly during or within a few hours of the procedure. All had been treated with the Farawave catheter (Boston Scientific), the most widely used for PFA during the study period. Based on estimated procedure volumes at that time, fatal arrhythmic events occurred at a rate of about 3.2 per 100,000 ablations with the Farawave catheter, including about 1.8 deaths from ventricular tachycardia or fibrillation per 100,000 cases.

A prior study suggested a rate of fatal ventricular arrhythmias closer to 30 out of every 100,000 procedures, Tilz noted, saying that “it’s most likely that the true incidence of ventricular events is significantly underreported.”

Still, in a relative sense, the researchers estimated that PFA was associated with roughly double the risk of death compared with the thermal technologies (RR 2.08; 95% CI 1.61-2.67).

Moreover, the EMBOL-AF study indicated that between 2017 and 2024, PFA accounted for 4.8% of all ablation procedures. Over that same span, PFA was associated with 11.8% of ablation-related deaths in MAUDE, indicating a 3.7-fold greater risk of mortality compared with radiofrequency ablation.

A Call for More Data

Commenting for TCTMD, Daniel Morin, MD (University of California, San Francisco), pointed out some limitations of the MAUDE database, saying that it’s more likely that adverse events occurring with use of a novel technology like PFA will be reported than those occurring with use of an established technology.

“You’d probably have to take this with a grain of salt,” he said.

Regarding causes of death, “certainly there does seem to be some question of a signal” when it comes to arrhythmic events occurring after PFA, he said. “And a lot of us are concerned about that.”

It’s difficult to identify an exact mechanism, “but if there’s a signal, we will find out what it is,” Morin said. The findings “makes you perk your ear up and recognize that there might be a problem happening,” he added. “I don’t know if it’s actionable information at present, but it’s certainly something that is fodder for research going forward.”

Reddy agreed that it’s important to look at this, though he still believes PFA is safer overall compared with the thermal technologies. He pointed out that periprocedural arrhythmic events can occur with radiofrequency and cryoballoon ablation as well, though probably at lower rates.

“Again, these are highly infrequent events, thankfully,” he said. “But we have to study it.”

Tilz concluded his presentation by calling for a better understanding of PFA technology through use of a mandatory prospective safety registry and standardized complication reporting. “We need better data in order to improve the technology and use [of] PFA technology, not only for the benefit of the physicians and the companies, but, most of all, for the benefit of the patients,” he said.

Overall, Tilz told TCTMD, PFA and the thermal catheters should be considered safe to use. But the information from this and other studies can be used when speaking with patients about their options, he said.

When undergoing thermal ablation, patients should be made aware of the risks of atrioesophageal fistula, tamponade, and stroke and when opting for PFA, patients should be told about the risks of tamponade, stroke, and fatal arrhythmias, he advised, adding that consideration might be given to extending monitoring periods after ablation to watch for arrhythmic complications.