The Micra transcatheter pacing system may be considered medically necessary in individuals when both conditions below are met:
- The individual has symptomatic paroxysmal or permanent high-grade arteriovenous block or symptomatic bradycardia-tachycardia syndrome or sinus node dysfunction (sinus bradycardia or sinus pauses).
- The individual has a significant contraindication precluding placement of conventional single-chamber ventricular pacemaker leads such as any of the following:
- History of an endovascular or cardiovascular implantable electronic device (CIED) infection or who are athigh risk for infection
- Limited access for transvenous pacing given venous anomaly, occlusion of axillary veins or planned use of such veins for a semi-permanent catheter or current or planned use of an AV fistula for hemodialysis
- Presence of a bioprosthetic tricuspid valve
The Micra transcatheter pacing system is considered investigational in all other situations in which the above criteria are not met.
Per the FDA label, the Micra Model MC1VR01 pacemaker is contraindicated for individuals who have the following types of devices implanted:
- An implanted device that would interfere with the implant of the Micra device in the judgment of the implanting physician
- An implanted inferior vena cava filter
- A mechanical tricuspid valve
- An implanted cardiac device providing active cardiac therapy which may interfere with the sensing performance of the Micra device
As per the FDA label, the Micra Model MC1VR01 pacemaker is also contraindicated for individuals who have the following conditions:
- Femoral venous anatomy unable to accommodate a 7.8 mm (23 French) introducer sheath or implant on the right side of the heart (for example, due to obstructions or severe tortuosity)
- Morbid obesity that prevents the implanted device to obtain telemetry communication within <12.5 cm (4.9 in)
- Known intolerance to titanium, titanium nitride, parylene C,primerforparyleneC,polyether ether ketone, siloxane, nitinol, platinum, iridium, liquid silicone rubber, silicone medical adhesive, and heparin or sensitivity to contrast medical which cannot be adequately premedicated
As per the FDA label, the Micra Model MC1VR01 pacemaker should not be used in individuals for whom a single dose of 1.0 mg dexamethasone acetate cannot be tolerated because the device contains a molded and cured mixture of dexamethasone acetate with the target dosage of 272 μg dexamethasone acetate. It is intended to deliver the steroid to reduce inflammation and fibrosis.
For axillary transvenous pacemakers, there is a concern that leads, or the generator could be impacted by the recoil of using a firearm (e.g., rifles or shotguns).Thus, leadless cardiac pacemakers can provide an alternative for individuals who suffer lead fracture or malfunction from mechanical stress and may be considered when axillary venous access is present only on a side of the body that would not allow use of equipment producing such mechanical stress (e.g., a firearm).