Micra pacemaker

The world's smallest pacemaker Medtronic Micra Transcatheter Pacing System isn't much larger than a nickel. 

George Mormon isn’t sure he’ll be able to top this year's birthday present.

Just a month ago, Bryan Heart became the first in Nebraska to implant Micra, the world’s smallest pacemaker. Mormon was honored to be the first recipient, just two days after his 87th birthday.

Micra is one-tenth the size of a traditional pacemaker -- close to the size of a large vitamin.

It’s designed to treat patients with bradycardia, or those who have a slow or irregular heart rhythm of less than 60 beats per minute. Symptoms can be dizziness, fatigue, shortness of breath or fainting spells. The Micra pacemaker relieves symptoms by sending electrical impulses to the heart, increasing the heart rate.

Dr. Andrew Merliss, a cardiac electrophysiologist at Bryan Heart, was the first physician to place the new device. As someone who has put several thousands of pacemakers in patients, he said he was impressed with the advancements.

“In my lifetime I’ve actually seen the size of pacemakers go from a shopping cart that was pushed in front of the patient because all of the electronics were so big, down to miniaturization, which was then the size of a hockey puck,” Merliss said.

Next came the silver dollar size. Now, a little bigger than a bullet. But all pacemakers prior to Micra required what can be a little bit of an inconvenience at times -- wires.

With traditional pacemakers, wires have to be carefully intertwined through veins and screwed into the heart muscle to allow connection. Because the wires cross valves, infection is a possibility, which then often requires another expense of laser extraction.  

“Those wires are really subjected to heartbeats 80,000 times a day,” Merliss said. “Those wires get a little bit of use and curvature that can ultimately lead to those wires wearing out.”

Between tinier measurements and wireless use with Micra, Merliss calls it a “smaller, less invasive alternative.”

Unlike previous pacemakers, Micra isn’t inserted below the collarbone through incision, leaving a scar and lump. It’s placed via a vein in the leg and then passed up into the heart wall, where it’s attached by the device’s small prongs, eliminating any visibility.

“We had one stitch in the leg that stayed in overnight, came out the next day, and then really, the rest is history,” Merliss said. “And it’s a good history.”

Merliss said there seems to be only one issue so far -- Micra isn’t made for everyone.

Patients who choose Micra choose a battery life that will last 10 years.

“If your life expectancy isn’t going to be 10 years then maybe that technology should be reserved for somebody that’s generally healthy, and I think that George is,” he said.

The other complication that can eliminate patients is that right now, the technology can only pace one chamber.

“There are conditions where the top part of the heart and the bottom part of the heart don’t beat in sync,” Merliss said. “This specific indication is really only for patients who have atrial fibrillation.”

A slow rate for the bottom part of the heart was the case for Mormon, making him a perfect candidate.

But what left Mormon and his granddaughter, Briana Kramer, whom he calls his “guiding light,” in awe after the procedure, was the doctor’s ability to adjust the pacemaker’s parameters based on Mormon's needs and feelings.

And it’s all done by communicating through a computer that is able to tell Mormon’s device, “OK, don’t let the heart go below 60,” Merliss said.

“They really fine-tune it to him specifically, which is really nice because he’s, I guess, not the ‘normal senior,’” Kramer said with a laugh. “He’s normally up and moving.”

Recovery didn’t faze Mormon and his “up and moving” lifestyle. He was walking around five to six hours after the implant.

With the help of his team at Bryan Heart and “leaps in technology,” Merliss expects Mormon to be just the first of many more Micra patients.

"I like new technology that I really think is going to help patients,” he said. “That’s one of the reasons I love medicine so much -- there’s always something new. It’s never boring.”

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Reach the writer at 402-473-7223 or lesparrago@journalstar.com

On Twitter @linds_esparrago


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