Focus of the Report: This Health Technology Assessment (HTA) focuses on the use of the Micra transcatheter pacing system (TPS) (Medtronic Inc.) as a leadless alternative to traditional transvenous pacemakers (TVPMs) for the management of patients with bradycardia or atrioventricular (AV) block in the presence or absence of atrial fibrillation (AF).

Technology Description: The Micra TPS is a single-chamber right ventricular pacing device. The device senses electrical activity of the heart via electrodes within the device’s titanium capsule. Heart rhythm is monitored for bradycardia. Rate-adaptive pacing therapy is provided based on programmed pacing parameters. The Micra TPS is self-contained and does not require a surgical incision in the chest or intravascular leads. It is inserted via a 23-French catheter placed in the femoral vein and held in place within the right ventricle of the heart via nitinol tines that attach to the myocardium.

Controversy: Leadless PMs have become an attractive option in an attempt to avoid complications associated with the transvenous leads in traditional TVPMs. However, LCPs are presently limited to single-chamber ventricle placement, which comprise a minority (< 10%) of all PMs. Leadless dual-chamber pacing or implantable cardioverter-defibrillator devices are not available at this time. Compatibility with other implanted devices, such neurostimulators, is unknown at present. Battery longevity is estimated at 7 to 12 years, depending on the programmed parameters, although longitudinal empirical evidence is needed.

Key Questions:

  • Is the Micra Transcatheter Pacing System (TPS) effective in treating symptomatic paroxysmal or permanent high-grade atrioventricular (AV) block in the presence or absence of atrial fibrillation (AF), symptomatic bradycardia-tachycardia syndrome, or sinus node dysfunction (SND)?

  • How does the Micra TPS compare with transvenous pacemakers (TVPMs) or other leadless cardiac pacemakers (LCPs) (e.g., the Nanostim)?

  • Is the Micra TPS safe?

  • Have definitive patient selection criteria been identified for the Micra TPS?

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