Micra Pacemaker

micra pacemakerMultiCare’s Pulse Heart Institute is now implanting the world’s smallest pacemaker, a one-piece, pill-sized device that is 93 percent smaller than conventional pacemaker designs which date back more than 50 years.

The self-contained Micra Transcatheter Pacing System is used to control heart rate for patients with bradycardia, a slow or irregular heart rhythm (usually fewer than 60 beats per minute). Traditional pacemakers rely on long leads (wires) that carry electrical pulses into the heart from a separate unit implanted in the patient’s chest. These systems can present a source of infection, and the leads can become vulnerable to damage or fractures over time.

The Micra is implanted directly into the right ventricle of the heart through a catheter in the leg; once placed, it is anchored by small tines. This one-piece design eliminates many of the risks for complication associated with systems that use leads. According to manufacturer Medtronic, trials have shown a 48% lower rate of major complications.

Tariq Salam, MD, Heart Rhythm Service Medical Director for Pulse Heart Institute, performed the first Micra implant in November 2018 at MultiCare Tacoma General Hospital, and Ellie Mueller, MD, implanted the first Micra at MultiCare Deaconess Hospital in March 2019. Dr. Salam says the new implant offers patients clear advantages from a cosmetic perspective.  “This type of pacemaker leaves no scar or device on the chest,” he says. “In fact, one of the hospitalists did not believe that the patient who got our first device actually had a pacemaker, since he could not find any scar.”

He adds that the device is especially useful in patients who are thin, or who have repetitive motion of the upper extremities. There are also fewer restrictions on activities after it is implanted.  “For years we have had patients who needed pacemakers but had body shapes that were not ideal for a traditional pacemaker,” Dr. Salam says. “In addition, there were patients who we worried about having lead complications. Now we can sleep better.”

The Micra has a 12-year battery life, and is approved for Medicare reimbursement. It was approved for use in the United States on April 6, 2016, and was cited by U.S. News & World Report as one of 2016’s “Biggest Achievements in Medicine.”

Common causes of bradycardia include congenital heart disease, side effects of certain heart medications, aging, scar tissue from previous heart attack, sick sinus syndrome (also called sinus node dysfunction and heart block, when the electrical impulse that travels from the upper to the lower chamber of the heart is irregular or blocked).  Some symptoms of bradycardia include dizziness, fainting, chronic lack of energy and shortness of breath.