title: Early Performance and Safety of the Micra Transcatheter Pacemaker in Pigs.
abstract: BACKGROUND
  The Micra® Transcatheter Pacing System (TPS; Medtronic Inc., Minneapolis, MN, USA) is a miniaturized single-chamber pacemaker system that is delivered via catheter through the femoral vein. In this study, the electrical performance was compared between the TPS and a traditional leaded pacemaker. In addition, the safety profile of the two systems was compared by thorough monitoring for a number of adverse events.
  
  
  METHODS
  The TPS was implanted in the right ventricular apex of 10 Yucatan mini pigs and a Medtronic single-lead pacemaker (SLP) was implanted in the right ventricular apex of another 10 pigs and connected to a traditional pacemaker. The electrical performance of all devices was monitored for 12 weeks. The safety profile of each system was characterized using x-ray, computed tomography, ultrasound, blood work, and necropsy to monitor for a variety of adverse events.
  
  
  RESULTS
  At implant the mean pacing thresholds were 0.58 ± 0.17 V @0.24 ms and 0.75 ± 0.29 V @0.21 ms for the TPS and the SLP respectively. After 12 weeks, mean thresholds were 0.94 ± 0.46 V and 1.85 ± 0.75 V (P < 0.0001). There were two pulmonary emboli that were small and past the tertiary branch, and one occurred in each arm. There were also two infections with one in each arm. There were no dislodgements (macro or micro), tissue injury, tamponade, or valve injury.
  
  
  CONCLUSIONS
  Overall, despite the 10-fold size reduction of the Micra TPS, it appears to perform similarly and have a similar safety profile to a traditional pacemaker system.
authors.affiliation: Medtronic CRHF Research, Mounds View, Minnesota.
authors.forename: Matthew
authors.initials: M
authors.lastname: Bonner
authors.affiliation: Medtronic CRHF Research, Mounds View, Minnesota.
authors.forename: Michael
authors.initials: M
authors.lastname: Eggen
authors.affiliation: Medtronic CRHF Numerical Modelling, Mounds View, Minnesota.
authors.forename: Tarek
authors.initials: T
authors.lastname: Haddad
authors.affiliation: Medtronic CRHF Research, Mounds View, Minnesota.
authors.forename: Todd
authors.initials: T
authors.lastname: Sheldon
authors.affiliation: Medtronic CRHF Systems Engineering, Mounds View, Minnesota.
authors.forename: Eric
authors.initials: E
authors.lastname: Williams
mesh_terms: D000818:Animals; D002404:Catheterization; D004867:Equipment Design; D004869:Equipment Safety; D005260:Female; D006352:Heart Ventricles; D008297:Male; D010138:Pacemaker, Artificial; D013552:Swine; D013556:Swine, Miniature
keywords: miniaturization; new technology; pacemaker; transcatheter pacing system