ESC 2021: Medtronic's miniaturized, leadless implant improves long-term safety over traditional pacemakers in real-world study

A real-world study of Medtronic’s leadless pacemaker showed it led to fewer complications—with fewer patients having to return to the operating room—compared to wired cardiac implants over a period of two years.

The company’s inch-long Micra pacing system, about a tenth the size of a traditional pacemaker, is placed within the heart’s chambers through a minimally invasive, catheter-based procedure. The device attaches directly to the wall of the right ventricle, forgoing the task of attaching separate electrodes to the heart muscle, as well as the need for a surgically created pocket to house the larger hardware.

Through an analysis of Medicare claims data spanning more than 16,000 beneficiaries, researchers found the leadless device delivered a 38% drop in reinterventions and a 31% reduction in chronic complications compared to transvenous pacemakers, according to Medtronic, which described the effort as the largest evaluation of leadless pacemakers to date.

"There is considerable evidence supporting the safety and efficacy of leadless pacemakers, but limited data evaluating their long-term outcomes compared to traditional pacemakers in a real-world setting," said Jonathan Piccini, director of cardiac electrophysiology at Duke University Medical Center, who presented the study’s findings at the annual congress of the European Society of Cardiology.

The Micra's size compared to a traditional
pacemaker (Medtronic)

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The study showed less frequent system revisions and device removals as well as fewer cases where patients needed to be upgraded to cardiac resynchronization therapy.

In addition, Micra’s transcatheter approach was largely taken among sicker patients including those with higher rates of end-stage renal disease and kidney dysfunction. Still, researchers found no differences in adjusted all-cause mortality after two years compared to those who received a traditional pacemaker.

Medtronic’s first leadless pacemaker received a CE mark in Europe in 2015, and the FDA approved it in 2016. In January 2020, the U.S. agency greenlighted a new version of the device, which includes accelerometers that detect each beat of the heart muscle, so it can adjust its electrical pacing to be in sync. All told, the medtech giant estimates that more than 100,000 people have received a Micra device worldwide.

The market’s other leadless pacemaker—St. Jude Medical’s Nanostim, since acquired by Abbott—saw a recall in 2016 and 2017 after reports of dropped telemetry and heart pacing as well as incidences (PDF) of broken docking hardware designed to allow the device to be easily removed by a catheter at the end of its battery life.