Leadless pacemaker tine damage and fracture: novel complications of a novel device fixation mechanism

Abstract

Background: Leadless pacemakers represent a paradigm-changing advancement. However, they required innovative and novel device design, including the use of nitinol tines for fixation.

Objective: We aimed to understand the potential for fracture in the novel tine-based fixation mechanism.

Methods: A retrospective approach was used to search the MAUDE (Manufacturer and User Facility Device Experience) database for events related to Micra pacemaker tine fracture and damage. Review of each report was performed to ascertain frequency of tine fracture and damage.

Results: Of 4241 MAUDE reports (2104 Micra VR, 2167 Micra AV), 230 included the terms "fracture" or "tine," which yielded 7 tine fractures and 19 reports of tine damage. Overall, 2 (29%) of 7 tine fractures were noted during implantation, whereas 2 (29%) of 7 were discovered ≥1 week after implantation; 5 (71%) of 7 tine fracture reports described no associated patient signs or symptoms, and 4 (57%) of 7 described no change in pacing parameters. Tine damage occurred during implantation in 16 (84%) of 19, compared with 2 (11%) of 19 noted ≥1 week after implantation; 15 (79%) of 19 tine damage cases reported no associated signs or symptoms, and 7 (37%) of 19 described no changes in pacing parameters. Among all cases, there was 1 case of device embolization.

Conclusion: The novel tine-based fixation mechanism appears susceptible to a novel failure mechanism-tine fracture and/or damage. Our analysis suggests these events may not always be associated with adverse signs or symptoms. Diligent attention at implantation, and future bench or clinical studies are needed to understand the rate, clinical impact, and mechanism of such failures, and role of surveillance.

Keywords: Complication; Failure; Leadless pacemaker; MAUDE; Tine fracture.

Figure 1

Timing of the discovery of tine fractures (n = 7) and tine damage (n = 19) in relation to implantation procedure of Micra leadless pacemakers. Reports of tine fracture or damage occurring during the implantation procedure are designated as “during implantation.” There were no reports of tine fracture or damage within 1 week of the implantation procedure. Tine fractures and damage occurring >1 week postimplantation are designated as such. Several reports did not specify how much time had elapsed from implantation to tine fracture or damage; these reports were categorized as “unclear.”