Dissolving Pacemaker in the Works

An experimental temporary pacemaker that is miniaturized, externally powered, and fully bioresorbable is being developed.

The 1-cm-diameter device successfully triggered ventricular activation in mouse, rabbit, and human heart tissue and in live animals, according to an early study released at the virtual annual conference of the Heart Rhythm Society.

The device could pace the heart for up to 32 days and be implanted with bioadhesive, Rose T. Yin, BS, a graduate student at Washington University in Washington, D.C., and colleagues reported.

"We're creating a device without a battery that's so small we can implant them in a much safer way than traditional temporary pacemakers. Then it will be absorbed when its work is finished," co-author Igor Efimov, PhD, also of George Washington University, told MedPage Today. "Or in another implementation, they may not need to be absorbed: if it doesn't have a battery, you could potentially make them last for a very long time."

When describing an earlier version of the device in a Nature Communications report in December, the group called it "a highly miniaturized wireless energy-harvesting and digital communication electronic for thin, miniaturized pacing platforms weighing 110 mg with capabilities for subdermal implantation and tolerance to over 200,000 multiaxial cycles of strain without degradation in electrical or optical performance."

In humans, the device could be powered by a 10-cm-diameter coil attached to the skin that wirelessly provides power to the pacemaker, Yin told MedPage Today. The power system would work just like the connection between a wireless charging mat and a smart phone, she said.

The new study reported on the bioresorbability of the pacemaker and the successful use of a bioadhesive that's designed to lower the risk of infection by avoiding the use of sutures or screws.

The pacemaker is covered by soluble glass that dissolves after a certain amount of time based on its thickness, Efimov said. Essentially, he said, "the thickness of the glass preprograms the lifetime of the device."

Such a device could be particularly useful in patients who need a pacemaker but have an infection, Faisal Merchant, MD, of Emory University in Atlanta, told MedPage Today. "The temporary pacemaker can be used as a bridge until the infection is treated, and then a permanent device is implanted."

Another similar scenario would be patients with transient injury to the conduction system, such as from cardiac surgery or implantation of transcatheter valves, he added.

Researchers are trying to find better alternatives, Merchant said. "Battery-free devices, options for harvesting energy, biologic pacemakers and other such technologies have been talked about for many years but most haven't gotten close to clinical translation."

The early data with the novel device "certainly sounds promising and valid," he said. "However, a major challenge would be how to deliver this technology to a human heart. These devices were implanted by open-heart surgery in rodents and application of these electrodes to the outside surface of the heart. Such a major operation for a temporary pacing system wouldn't gain any traction in humans. A minimally invasive alternative would be needed."

More rigorous studies with large animals, such as pigs, would be the next step prior to human trials, Yin said.

Comment