In April 2016, the FDA approved the first leadless pacemaker, Micra, developed and manufactured by Medtronic, for clinical use in patients in need for a single chamber pacemaker, to treat slow heartbeats (bradycardia). Globally, Medtronic reports, there have been already 10,000 implants.
This is a completely novel concept of pacing. The traditional pacing systems are implanted surgically into the tissue underneath the collarbone and lead(s) are threaded through a vein into the heart’s ventricle (pumping chamber). The leads stay in the circulation and are attached to the pacemaker battery.
The leadless pacemaker on the other hand is inserted through a vein in the groin and is then passed via a specialized delivery system directly into the right pumping chamber, where it stays permanently. There are no leads attached to the pacing capsule. So far, this system can pace only the right pumping chamber and is thus a single-chamber pacemaker.
During a very recent electrophysiology meeting in Japan, researchers reported excellent implant success rate with very low complication rate in the hands of implant novices, which we all are with this new technology. With growing experience, the numbers of complications will even further diminish.
Although the Micra leadless pacing system is approved for anybody who has a need for a single chamber pacemaker, I believe that not everybody needs and should get it. It definitely has a niche in certain circumstances, for example, when a patient has no access to the heart through the subclavian veins, which could be thrombosed from radiation therapy or other reasons, dialysis patients with fistulas in both arms, in patients with recurrent skin infections with high risk of infections migration into the pacemaker pocket and onto the leads, in patients who undergo radiofrequency ablation of the AV node for atrial fibrillation and require a reliable and stable post procedure implant, as their life becomes completely dependent on the pacemaker function. These are just a few examples, and every decision will need to be individualized.
This new technology sounds very promising and will most likely develop into a dual chamber system fairly quickly, but it is still very young, and the data is limited to a short observation period. We cannot know yet, what late problems we may encounter in five or ten years from now. After these pacemakers have been in the heart for several years, they overgrow with dense scar tissue, thus removal is extraordinarily difficult if not impossible. Therefore, especially in younger population, one has to clearly assess the indications for leaderless versus a traditional pacemaker system, as in their life span, they will need several pacemakers. Lastly, there still is a significant cost difference between these systems.
This is clearly a very exciting technology and is rapidly establishing its place in the arrhythmia management.