Extraction of a dislocated leadless pacemaker in a patient with infective endocarditis and repeated endocardial and epicardial pacing system infections

[Leadless pacemakers : A "permanently" good solution?]

The two currently available leadless pacemakers are highly effective and safe in the respective approval studies and also real-world registries. Compared to conventional pacemakers, there are lower long-term complication rates compared to conventional pacemaker systems (especially regarding lead dislocations and systemic infections). Increasing evidence (currently largely for the Micra™ [Medtronic, Minneapolis, MN, USA] device) shows that these advantages are also valid in the long-term. Leadless pacemakers can therefore be regarded a "permanently good solution", when appropriately implanted in suitable patients.

Lost but Not Lost-Embolization of a Leadless Pacemaker to the Pulmonary Artery with Consecutive Endovascular Recovery

Background: Leadless transcatheter pacemaker systems (TPS) have become a valuable alternative to transvenous pacemakers in selected indications. With the steadily increasing amount of TPS implantations performed worldwide, reports of periprocedural complications are likewise increasingly found in the literature but are still underreported. Case presentation: We report a case of a 75 year old male undergoing TPS implantation due to cardioinhibitory vasovagal syncope. The implantation was primarily uneventful; adequate pacing parameters and fixation of the device were achieved. Unfortunately, dislocation of the leadless pacemaker occurred at the end of the procedure and the device embolized into a primary side branch of the right pulmonary artery. Endovascular retrieval was performed by using a single snare technique without any further complications. Conclusions: Although challenging, endovascular recovery of embolized TPS from the pulmonary artery is feasible and may be successfully accomplished by experienced implanters.

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. Both groups underwent histopathological evaluation. Pacing capture thresholds (PCTs), p wave amplitude, and pacing impedances were measured chronically. Device retrieval times were recorded, and intracardiac echocardiography was used.

RESULTS

At 24 weeks, PCTs for group 1 were low and stable for both the first device (0.55 ± 0.14 V) and the second device (0.57 ± 0.09 V), in which the average retrieval time was 17:35 minutes. For group 2, the average retrieval time was 6:12 minutes, chronic PCTs in the first device were 0.53 ± 0.11 V, and acute PCTs for the second device were 0.71 ± 0.19 V. Pathological findings were within an expected range of tissue responses for similar Micra acute and chronic implants and device retrievals. p waves and impedances were stable and within an expected range for implant site and electrode design. Complications included 1 early dislodgment and 1 death attributed to a prototype retrieval tool.

CONCLUSION

In an animal model, an atrial Micra can be easily implanted with excellent chronic pacing performance and is easily retrievable at 6 months. A second device can successfully be implanted with low, chronic stable thresholds. A developed prototype retrieval tool was easy to use and, with modifications, complication free.

[Micra™ leadless pacemaker : Clinical experience and perspectives]

Leadless pacemakers have the potential to fundamentally change the field of device therapy. As leads and generator pockets are no longer needed with this technology, many potentially dangerous complications of conventional pacemaker systems like lead fractures, lead endocarditis or pocket infections can be effectively avoided. At present, Micra™ (Medtronic Inc., Minneapolis, MN, USA) is the only commercially available leadless pacemaker. Since its first-in-human implantation in 2013, thousands of these devices have been implanted worldwide. This article presents an overview of the present clinical evidence and future perspectives of this promising new technology.