Abstract Body (Do not enter title and authors here): Background
Leadless pacemakers (LP) avoid the pocket and lead-related complications of transvenous pacing. A potential complication of LPs is dislodgement and/or embolization (D/E) during or after implant. No D/E occurred in the original 725-patient Micra™ VR clinical trial. However, in the 526-patient LEADLESS II-phase 2 trial, the rate of dislodgement for 200 Aveir™ VR LPs was 1.5%. Thus, there appears to be a significant difference in D/E rates between these LPs that have different fixation mechanisms and insertion tools.

Aims
We aimed to determine if the Aveir VR LP has continued to exhibit D/E since it was approved by the Food and Drug Administration (FDA) in April 2022.


Methods
We queried the FDA's Manufacturers and User Facility Device Experience (MAUDE) database for Aveir D/E that occurred in the U.S. and were reported by the manufacturer from April 2022-December 2023. The number of Aveir VR implants in the U. S. was obtained from the manufacturer's publicly available product performance report. D/E outside the U.S. were excluded.


Results
During the 21 months, 55 of 3,139 (1.75%) Aveir VR implants exhibited D/E. More D/E (34;61.8%) occurred during implant, with 18 (52.9%) of these happening after release of the device from the tether mode. Fourteen (41.2%) of the intra-procedural D/E occurred when the device prematurely released from the delivery catheter, and two dislodged during cardiopulmonary resuscitation (CPR). D/E occurred in 21 patients (38.2%) after implant and were signified by loss of pacing or inability to interrogate the device. Four (19%) out of those 21 patients presented with symptomatic bradycardia. The dislodged devices commonly embolized to the pulmonary artery and right atrium/vena cava. LP retrieval was successful in 49 (89%) cases. Thirty-two patients (58.1%) received a new LP, 5 patients were transitioned to a transvenous system, and a replacement device was not specified for 17 (31%) patients. One patient died during implantation due to ventricular fibrillation (VF) not related to D/E.


Conclusions
Fixation issues and premature separation of the device from the delivery catheter appear to be responsible for most of these D/E. Studies are needed to determine if impedance or another metric is associated with adequate Aveir fixation. The manufacturer should address the premature separation problem with Aveir. Success of D/E retrieval may be related to tools specific for Aveir. Further studies are needed to compare between the two LPs.