How to Implant a Leadless Pacemaker With a Tine-Based Fixation.

Two major studies have shown that leadless pacemakers are safe and effective for patients requiring right ventricular rate responsive pacing therapy. This positive result recently led to FDA approval of one of the available leadless pacing devices. While this new technology is promising, it requires a different skill set for safe implantation. In this article, we review in detail the different steps required for implantation of tine-based leadless pacemakers while providing tips and tricks to minimize complications.

Right Ventricular Anatomy Can Accommodate Multiple Micra Transcatheter Pacemakers.

BACKGROUND: The introduction of transcatheter pacemaker technology has the potential to significantly reduce if not eliminate a number of complications associated with a traditional leaded pacing system. However, this technology raises new questions regarding how to manage the device at end of service, the number of devices the right ventricle (RV) can accommodate, and what patient age is appropriate for this therapy. In this study, six human cadaver hearts and one reanimated human heart (not deemed viable for transplant) were each implanted with three Micra devices in traditional pacing locations via fluoroscopic imaging. METHODS: A total of six human cadaver hearts were obtained from the University of Minnesota Anatomy Bequest Program; the seventh heart was a heart not deemed viable for transplant obtained from LifeSource and then reanimated using Visible Heart(®) methodologies. Each heart was implanted with multiple Micras using imaging and proper delivery tools; in these, the right ventricular volumes were measured and recorded. The hearts were subsequently dissected to view the right ventricular anatomies and the positions and spacing between devices. RESULTS: Multiple Micra devices could be placed in each heart in traditional, clinically accepted pacing implant locations within the RV and in each case without physical device interactions. This was true even in a human heart considered to be relatively small. CONCLUSIONS: Although this technology is new, it was demonstrated here that within the human heart's RV, three Micra devices could be accommodated within traditional pacing locations: with the potential in some, for even more.

To retrieve, or not to retrieve: System revisions with the Micra transcatheter pacemaker.

BACKGROUND: Early experience with leadless pacemakers has shown a low rate of complications. However, little is known about system revision in patients with these devices. OBJECTIVE: The purpose of this study was to describe the system revision experience with the Micra Transcatheter Pacing System (TPS). METHODS: Patients with implants from the Pre-market Micra Transcatheter Pacing Study and the Micra Transcatheter Pacing System Continued Access Study (N = 989) were analyzed and compared with 2667 patients with transvenous pacemakers (TVPs). Revisions included TPS retrieval/explant, repositioning, replacement, or electrical deactivation (with or without prior attempt at retrieval, generally followed by TVP implant) for any reason. Kaplan-Meier revision rates were calculated to account for varying follow-up duration and were compared using a Fine-Gray competing risk model. RESULTS: The actuarial rate for revision at 24 months postimplant was 1.4% for the TPS group (11 revisions in 10 patients), 75% (95% confidence interval 53%-87%; P < .001) lower than the 5.3% for the TVP group (123 revisions in 117 patients). TPS revisions occurred 5-430 days postimplant for elevated pacing thresholds, need for alternate therapy, pacemaker syndrome, and prosthetic valve endocarditis; none were due to device dislodgment or device-related infection. TPS was disabled and left in situ in 7 cases, 3 were retrieved percutaneously (range 9-406 days postimplant), and 1 was surgically removed during aortic valve surgery. CONCLUSION: The overall system revision rate for patients with TPS at 24 months was 1.4%, 75% lower than that for patients with TVPs. TPS was disabled and left in situ in 64% of revisions, and percutaneous retrieval was successful as late as 14 months postimplant.