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Published on March 01, 2018

Leadless Pacemaker Reduces Complications, Improves Recovery

Micra pacemaker implanted in heartUnlike conventional transvenous pacemakers, the
Micra is implanted directly into the patient's heart.

North Kansas City Hospital is the first hospital in the Northland to implant the smallest pacemaker in the world. About the size of a large vitamin capsule, the Micra™ Transcatheter Pacing System is a leadless, self-contained device that is implanted directly into a patient’s right ventricle, where it generates electrical impulses to pace the heart.

“The Micra is not indicated in those who need dual-chamber pacing. It is ideal for individuals with chronic AFib who have slow ventricular rates or long ventricular pauses, which often can lead to syncope,” said L. Brick Rigden, MD, FACC, an electrophysiologist with Meritas Health Cardiology.


Micra vs. Traditional Pacemaker

An 18-month clinical trial compared the Micra with traditional pacemakers. In “Long-term Performance of a Transcatheter Pacing System: 12-month Results From the Micra Transcatheter Pacing Study” published in the May 2017 Heart Rhythm, researchers found few patients experienced major complications through 12 months of follow-up, and all patient subgroups benefited compared with a transvenous pacemaker historical control group.

Of the 720 patients implanted successfully at 56 centers throughout the world between December 2013-May 2015, 96% were free from major complications. The risk of major complications was 48% lower in patients with Micras than control patients with transvenous systems. Across age, sex and comorbidities, the Micra was associated with a lower risk of major complications compared with transvenous pacemakers, and there were no subgroups where the Micra showed a higher risk. Pacing thresholds remained low and stable through 24 months of follow-up.

The technology offers several advantages over a standard pacemaker:

  • Fewer complications
  • Return home within one day of the procedure
  • Resume normal activities within 24 hours of returning home
  • Compatible with 1T and 3T MRI scanners

The Micra also eliminates the need for transvenous leads and a subcutaneous pocket, which, although rare, can cause complications such as a pneumothorax, pocket hematoma or pocket infection. “Long-term, that can mean lead fracture, lead infection and venous occlusion around the leads going through the subclavian vein,” said Dr. Rigden, who is board certified in cardiology and electrophysiology.

Unlike a wired pacemaker, the Micra eliminates lead dislodgement because it’s anchored in the heart. “If a patient has a wired pacemaker, we restrict them from arm movement for four to six weeks because vigorous arm activity could dislodge the leads, which would require surgery to reposition those leads,” Dr. Rigden explained.

He noted some patients are not candidates for conventional pacemakers because vascular issues make insertion problematic. “Some people have a blocked subclavian vein, indwelling catheter or fistula for dialysis,” Dr. Rigden explained.


Micra DeviceThe Micra is 93% smaller than conventional pacemakers.

During the procedure, Dr. Rigden inserts a 41-inch catheter to move the Micra through the patient’s femoral vein and into the heart’s right ventricle. He places the device against the heart wall, securing it with tiny flexible prongs. After testing to make sure the device is working properly, Dr. Rigden removes the catheter. From pre-op to post-op, procedure time is about one hour.

Because there are no lead wires to monitor, patients do not require long-term follow-up. Instead, they are evaluated quarterly through remote monitoring. The miniaturized capsule has a 12-year average battery life, which is the same as a traditional pacemaker. After that time, as many as three more Micras can be implanted over time.

Dual-chamber Horizon

Although the Micra is only indicated for the right ventricle, Dr. Rigden is optimistic about what the future holds.

“A dual chamber device is being developed,” Dr. Rigden said. “With one implanted in the atrium and one in the ventricle, they would be able to talk to one another and pace the heart’s upper and lower chambers."

L. Brick Rigden

L. Brick Rigden, MDDr. Rigden earned his medical degree from the University of Missouri, Columbia. He completed his cardiology residency at the University of Iowa Hospitals and Clinics, Iowa City, and cardiac electrophysiology fellowship at Indiana University Medical Center, Indianapolis.