Key result
Varipulse PFA is linked to ~3x more neurologic events but fewer cardiovascular events than Affera.
Why the study?
Two pulsed field ablation catheter systems for AF are widely adopted, but their comparative real-world safety is unknown.
Does the Affera Sphere-9 pulsed field ablation catheter have a different reported safety profile compared to the Varipulse catheter in real-world practice?
Observational (n=1,104)
Does the Affera Sphere-9 pulsed field ablation catheter have a different reported safety profile compared to the Varipulse catheter in real-world practice?
Absolute Event Rate: 44.3% vs 14.8%
p-value: p=<0.001
Real-world FDA MAUDE reports suggest distinct safety signatures for two pulsed field ablation systems, with Varipulse showing more neurologic events and Affera showing more cardiovascular/arrhythmic events, though true incidence rates remain unknown.
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“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.”
“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. 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.”
“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”
Distinct reported safety signals between PFA systems warrant device-specific monitoring; leaves open whether differences reflect true risk or reporting bias.
BACKGROUND: Two pulsed field ablation (PFA) catheter systems for atrial fibrillation (AF) are widely adopted: the Affera Sphere-9 (Medtronic) and the Varipulse (Biosense Webster). Their comparative real-world safety is unknown. METHODS: We searched the FDA MAUDE database (June 27, 2026) for all reports naming either catheter since U.S. release. After excluding duplicates and non-catheter components, 743 Affera and 361 Varipulse reports remained. Reports were classified by FDA Event Type (device- vs. patient-related) and complication status, with complications grouped by organ system. Proportions were compared with chi-square or Fisher exact tests in R 4.3.3. RESULTS: Neurologic events were far more frequent among Varipulse reports (44.3 % vs. 14.8%; P < 0.001), driven by stroke (38.0% vs. 9.7%; P < 0.001). Cardiovascular events predominated among Affera reports (43.2% vs. 29.1%; P < 0.001), including ventricular fibrillation (52 vs. 1), heart block (8.7% vs. 1.4%; P < 0.001), and hypotension (5.5% vs. 0.8%; P<0.001); effusion/tamponade was more frequent with Varipulse (15.2% vs. 9.0%; P = 0.003). Complication-free reports were more frequent with Affera (35.3% vs. 21.1%; P < 0.001). Deaths did not differ (2.6% vs 1.4%; P = 0.30). CONCLUSIONS: These PFA systems show distinct reported safety signatures: neurologic/stroke-predominant for Varipulse and cardiovascular/arrhythmic (ventricular fibrillation, heart block) for Affera. Because MAUDE lacks procedural denominators, these proportions describe reported events, not incidence. Prospective, patient-level studies are needed to establish causation.
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Shoura et al. (2026) conducted an observational in Atrial fibrillation (n=1,104). Varipulse pulsed field ablation catheter vs. Affera Sphere-9 pulsed field ablation catheter was evaluated on Neurologic events (p=<0.001). In FDA MAUDE reports, the Varipulse PFA catheter had more frequent neurologic events (44.3% vs 14.8%; P<0.001), whereas Affera had more cardiovascular events (43.2% vs 29.1%; P<0.001).
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