Another Leadless Pacemaker Passes the Test

Summary and Comment |
November 9, 2015

Another Leadless Pacemaker Passes the Test

  1. Mark S. Link, MD

A year after similar results, a second leadless pacemaker has met short-term safety and efficacy goals.

  1. Mark S. Link, MD

A leadless pacemaker would address a key downside of the current transvenous system: the weak link between the pacemaker generator and the heart. In addition, the lack of a generator placed in the subcutaneous tissue would avoid pocket hematomas and infections. Recently, interim results from the clinical study of the St. Jude Nanostim leadless pacemaker were favorable (NEJM JW Cardiol Oct 2 2015; [e-pub] and N Engl J Med 2015; 373:1125). Now, a manufacturer-sponsored trial reports that a second leadless pacemaker, the Medtronic Micra, also meets safety and efficacy goals.

The Micra study had a design similar to the Nanostim study: 6-month efficacy was assessed for the first 300 implants. Implants continued during follow-up, and these implants were included in the safety analysis. Implant success with the Micra was 99.2%. Serious adverse outcomes were observed in 4.0% of subjects, including cardiac perforation or pericardial effusion in 1.6%, but there were no dislodgements. The 6-month efficacy endpoint was met in 98.3% of patients.


These two studies show that leadless pacemaker technology works: Both single-chamber, right-ventricular-only pacemakers were as safe and effective as transvenous systems in short- term follow-up. Demonstration of the feasibility of leadless pacing will lead to an arms race in this technology. I would expect dual-chamber systems, and linkage with subcutaneous implantable cardioverter-defibrillators, to follow, paving the way for antitachycardia pacing for ventricular treatment.

Dr. Link is also the author of an editorial on this study.

Editor Disclosures at Time of Publication

  • Disclosures for Mark S. Link, MD at time of publication Grant / Research support Unequal Technologies Editorial boards UpToDate; Heart Rhythm Leadership positions in professional societies Heart Rhythm Society (Chair, CME Compliance Committee); American Heart Association (Chair, ACLS Writing Group; Member, Emergency Cardiovascular Care)


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