Abstract Body (Do not enter title and authors here): Introduction: Pulsed field ablation (PFA) is an adaptation of direct current ablation first used for catheter ablation in the 1980s. Expectations of a reduced risk profile led to the current resurgence in investment and interest in the technology as a potential alternative energy source for ablations to treat atrial fibrillation (AF). However, reports of adverse events, including new risks, are increasing.

Research Question: How many adverse effects are reported with the use of newly available PFA systems?

Aims: Quantify and describe the adverse events from PFA reported to date in the Food and Drug Administration’s (FDA) Manufacturer and User Facility Device Experience (MAUDE) database.

Methods: We searched the U.S. FDA’s MAUDE database for all reports filed with the code “QZI”, which is the product code for PFA systems created with the first FDA approvals in February 2024. All reports from inception through April 2024 (a total of 3 months) were included in this review. Per manufacturer presentation in May 2024, approximately 1000 cases utilizing PFA had been captured in a post-market registry of the predominant commercially used technology, but the exact number of cases can not be determined from MAUDE data.

Results: A total of 217 adverse events were reported over the first 3 months of US approval, with 91 of these considered patient injuries. These injuries included 10 cases of cardiac tamponade, 7 reports of postoperative arrhythmia, 6 instances of device-related tissue entrapment, 5 cases of hemolysis with impaired renal function, 5 cases of stroke or TIA, including both embolic and hemorrhagic, 3 cases of intraoperative heart block, 2 coronary spasms, and 2 cases of intraoperative ST elevation. (Figure) Of the 91 reported patient safety events, 46 required hospitalization, 13 cases required temporary pacing, 11 required pericardiocentesis, 4 required dialysis, 4 required cardiothoracic surgery, and 2 required cardioversion.

Conclusions: A number of adverse events have been reported to the MAUDE database in the first 3 months of FDA approval of PFA. The cardiac electrophysiology community should remain vigilant to ensure that the benefit-risk profile remains acceptable for patient safety.