Pacemaker Advancements
Written by W. Michael Kutayli, MD, Bryan Heart Electrophysiologist
Leadless pacemakers represent the latest in device technology and have revolutionized the treatment of bradycardia in recent years. Bryan Heart has been at the forefront of this revolution from the beginning and remains at its leading edge.
Leadless Pacemaker Origins
Initially envisioned in the 1970s, leadless pacemakers were successfully implanted in dogs using a mercury battery powered capsule. With advanced battery technology, communication capability, and catheter-based delivery systems leadless pacemakers became a reality.
The Micra Transcatheter Pacing system (Medtronic) received FDA approval in April 2016. Bryan Heart electrophysiologist Andrew Merliss, MD, implanted the first leadless pacemaker in Nebraska on July 6, 2016.
Leadless pacemakers are:
- 90% smaller than a transvenous pacemaker
- A self- contained generator and electrode system
- Implanted directly into the right ventricle via a femoral vein transcatheter approach
- requires no chest incision or subcutaneous generator pocket
The Micra attaches to the right ventricle myocardium via four linear self-expanding nitinol tines. Low-molecular weight heparin is administered preoperatively and during the procedure to prevent thrombosis. Complications may occur related to femoral vein access or need for device repositioning; there is moderate risk of cardiac perforation with subsequent pericardial effusion. Patients and providers should be aware that although cardiac perforation is a rare complication following pacemaker system implant procedures, the risk of major complications following cardiac perforation may be higher in patients who receive leadless pacing systems vs. traditional transvenous pacemakers.
Benefits of Leadless Pacemakers
The primary advantage of a leadless pacemaker is the elimination of several complications associated with transvenous pacemakers and leads, such as:
- Pocket infections
- Hematoma
- Lead dislodgement
- Lead fracture
The leadless pacemaker also has cosmetic appeal because there is no chest incision or visible pacemaker pocket. Leadless pacemakers are also designed to be compatible with magnetic resonance imaging.
At present, leadless pacemakers provide only single-chamber ventricular pacing and lack defibrillation capacity. Leadless pacemakers may be suitable for patients with:
- Permanent atrial fibrillation with bradycardia
- Tachycardia-bradycardia syndrome or
- Those who rarely require pacing
Until recently, leadless pacemakers were felt to be inappropriate for patients with certain forms of heart block.
Latest Leadless Pacers Hit the Market
Approved by the FDA in 2020, Micra AV™ looks like the original Micra. However, Micra AV™ has several additional and novel internal atrial sensing algorithms which detect cardiac movement, allowing the device to adjust pacing in the ventricle to coordinate with the atrium, providing “AV synchronous” pacing therapy. In a sense, it detects pressure changes that occur with atrial contraction—it has the ability to “listen” for intrinsic atrial activity. The Micra AV™ also delivers an estimated average battery longevity of eight to 13 years, dependent on patient’s degree of AV block. The first Micra AV™ was implanted at Bryan on March 20, 2020.
Bryan Heart Continues to help Pioneer Advances in Leadless Pacing
Abbott recently announced new, late-breaking data from the global Leadless II IDE study evaluating Abbott's investigational Aveir leadless pacemaker in patients with certain abnormal heart rhythms. The data shows the Aveir device met its pre-specified primary endpoints and suggest that the Aveir system, once approved, could offer new benefits for patients who require the use of a pacemaker to treat slow heart rhythms.
Abbott's Aveir system is the world's only leadless pacemaker specifically designed to be retrieved when the device needs to be replaced or if a patient's therapy needs to be changed. Abbott's investigational Aveir leadless pacemaker is currently being evaluated for FDA approval. Bryan Heart electrophysiologists will be involved in upcoming trials with the Aveir system that may eventually lead to the development of a leadless dual chamber pacemaker.
As always, Bryan Heart remains committed to providing the Midwest with the latest pacing technologies available.
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For questions or to refer a patient, please call 402-483-3333.
