May 1, 2017

World’s Smallest Pacemaker Reaches a Big Milestone

More than 6,000 patients have now received the revolutionary Micra pacemaker.

Minneapolis, Minn., May 1, 2017 -- Just two years after receiving CE Mark in Europe, and one year after FDA approval in the United States, Micra, the world’s smallest pacemaker, has passed another milestone.

Worldwide, more than 6,000 patients in over 30 countries are now receiving pacing therapy from a Micra device. The revolutionary pacemaker, which is about one-tenth the size of traditional pacemakers, is implanted directly into the heart and does not require the use of wires, or leads, that connect standard pacemakers to the heart.

Mary Lou Trejo, of Columbus, Ohio, was among the first in the United States to receive Micra. The miniaturized pacemaker was in clinical trials at the time of her procedure. Three years later, she says she’s doing well.

“I feel great,” she said. “My biggest news is that I started a new decade.” (She recently turned 80 years old). Learn more about Mary Lou and find out what her doctors say about Micra.

In the year since it was approved for use in the United States, Micra was also approved for coverage by Medicare, and named “2016’s Biggest Achievement in Medicine” by US News and World Report

Micra was the result of 10 years of development by Medtronic scientists, engineers and researchers, working to miniaturize medical devices. Watch a video about “deep miniaturization.”

Important Safety Information: Micra Transcatheter Pacing System  VVIR Single Chamber with SureScantm MRI


Micra Model MC1VR01 is indicated for patients with:

  • symptomatic paroxysmal or permanent high grade AV block in the presence of AF,
  • symptomatic paroxysmal or permanent high grade AV block in the absence of AF, as an alternative to dual chamber pacing when atrial lead placement is considered difficult, high risk, or not deemed necessary for effective therapy,
  • symptomatic bradycardia-tachycardia syndrome or sinus node dysfunction (sinus bradycardia/sinus pauses), as an alternative to  atrial or dual chamber pacing when atrial lead placement is considered difficult, high risk, or not deemed necessary for effective therapy.

Rate-responsive pacing is indicated to provide increased heart rate appropriate to increasing levels of activity.


Micra Model MC1VR01 is contraindicated for patients who have the following types of medical 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, or an implanted cardiac device providing active cardiac therapy that may interfere with the sensing performance of the Micra device.

The device is contraindicated for patients 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 from obtaining telemetry communication within ≤12.5 cm (4.9 in), or known intolerance to the materials listed in the Instruction for Use, or to heparin, or sensitivity to contrast media that cannot be adequately premedicated.

Steroid use – Do not use in patients for whom a single dose of 1.0 mg of dexamethasone acetate cannot be tolerated.

Warnings and precautions

End of Service (EOS)When the EOS condition is met, the clinician has the option of permanently programming the device to Off and leaving it in the heart, or retrieving the device, provided the device has not yet become encapsulated.  Removal of the Micra device after it has become encapsulated may be difficult because of the development of fibrotic tissue. If removal of the device is required, it is recommended that the removal be performed by a clinician who has expertise in the removal of implanted leads.

MRI conditions for useBefore an MRI scan is performed on a patient implanted with the Micra device, the cardiology and radiology professionals involved in this procedure must understand the requirements specific to their tasks as defined in the device manuals.

Rate-responsive mode may not be appropriate for patients who cannot tolerate pacing rates above the programmed Lower Rate.  Asynchronous VVIR pacing with sinus rhythm may not be appropriate when competitive pacing is considered undesirable or causes symptoms of pacemaker syndrome. The patient’s age and medical condition should be considered by physicians and patients as they select the pacing system, mode of operation, and implant technique best suited to the individual.

Precautions should be taken before administering anticoagulant agents, antiplatelet agents, or contrast media in patients with known hypersensitivity to these agents.

The use of deactivated Micra devices in situ and an active Micra device, or an active transvenous pacemaker or defibrillator, has not been clinically tested to determine whether EMI or physical interaction is clinically significant. Bench testing supports that implantation of an active Micra device, or an active transvenous pacemaker or defibrillator, next to an inactivated Micra device is unlikely to cause EMI or physical interaction. Post-approval studies are planned to characterize risks of co-implanted, deactivated Micra devices. Currently recommended end of device life care for a Micra device may include the addition of a replacement device with or without explantation of the Micra device, which should be turned off.

Potential Complications

Potential complications include, but are not limited to, toxic/allergic reaction, oversensing, acceleration of tachycardia, myocardial infarction and surgical complications such as cardiac perforation, pericardial effusion, cardiac tamponade, death, device embolization, access site hematoma and AV fistulae, vessel spasm, infection, inflammation, and thrombosis. 

See the device manuals for detailed information regarding the implant procedure, indications, contraindications, warnings, precautions, MRI conditions for use,  and potential complications/adverse events. For further information, please call Medtronic at 1-800-328-2518 and/or consult Medtronic’s website at

Caution: Federal law (USA) restricts these devices to sale by or on the order of a physician.