Implant, performance, and retrieval of an atrial leadless pacemaker in sheep.

Background: Medtronic is developing an atrial Micra Transcatheter Pacing System (Medtronic, Minneapolis, Minnesota) and associated retrieval system.

Objective: The purpose of this study was to evaluate chronic atrial Micra retrieval, reimplantation, and chronic pacing performance.

Methods: Sheep were implanted in 2 groups: group 1 (n = 6) for 6 months, a second device implanted, and first retrieved and studied for an additional 6 months; group 2 (n = 6) for 6 months, devices were retrieved, and a second device implanted and observed acutely.

Design and Evaluation of a Novel Fixation Mechanism for a Transcatheter Pacemaker.

Goal: The purpose of this paper was to evaluate a nitinol tine fixation design for a transcatheter pacemaker in order to determine if the tines could be easily deployed and safely removed from the myocardium, enable low, stable pacing thresholds, and minimize the potential for dislodgment.

Methods: The penetration properties of 13 human hearts were compared to the deployment and fixation energy of the tines to determine if the tines could be easily deployed and removed from the myocardium. The safety factor for dislodgement was calculated by comparing the kinetic energy of the device to the fixation energy of the tines.