Scientists devise a battery-free pacemaker that can be absorbed by the body

Scientists have designed a temporary, battery-free pacemaker that can be broken down by the patient’s body when its work is done, the latest advance in the emerging field of bioelectronics.

In a paper published this week in Nature Biotechnology, researchers report that the device reliably kept the heart’s pace in check in tests on mice, rats, and other animals, as well as in human heart tissue in a dish. And while the research is still in the early stages, the scientists say the pacemaker was able to overcome key limitations of existing devices.

“There are about 1 million people a year who receive pacemaker implantations worldwide. It’s a huge, huge medical field, but mostly pacemakers are permanent,” said Igor Efimov, a biomedical engineer and professor at George Washington University and co-author of the new paper.

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Unlike traditional pacemakers, which are left inside a patient for the rest of their life or until the battery dies, a traditional temporary pacemaker is implanted and later removed. The devices are typically for children with congenital heart defects or adults who have had a coronary artery bypass graft, who may need a temporary pacemaker to correct a slowed heart rhythm for only a few days or weeks.

A traditional temporary pacemaker has wires connected to the heart, which poke out of the skin and attach to external hardware. Some experts say that setup could raise the risk of infection, potentially injure the heart when the lead is removed, and can hamper patient mobility. Being able to move around after surgery is especially valuable as patients recover.

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“The patient will be more free to move around after the surgery,” said Moussa Mansour, director of the Atrial Fibrillation Program at Massachusetts General Hospital. Mansour, who was not involved in the research, added that “the more you keep the patient in bed, the more likely they are to develop clots in their legs or pneumonia” or other complications.

The new device overcomes some of those challenges with the help of an external coil that can be sewn into a patient’s shirt or placed as a patch on the patient’s chest, where it transmits energy to power the pacemaker.

“You know when you try to charge a phone wirelessly? It’s exactly the same principle,”  said Efimov.

Because all of the complex programming for the pacemaker is done not in the device itself, but in external hardware, it isn’t confined by circuits that would otherwise be needed to communicate and process heart information. That means the device can be tiny and thin — less than a millimeter thick — which makes it easier to implant.

“It’s restricted just by the size of the antenna, which will harness the energy,” said Efimov.

Efimov and his colleagues were able to build on past research into bioresorbable materials, which have been developed and used for other applications for years. They selected materials that could be slowly and safely absorbed by the body. The thickness or type of materials used can change depending on how long the temporary pacemaker needs to last. The materials — some organic, silicone-based, or metals like magnesium — are also relatively affordable and comparable to the costs of a typical pacemaker, according to Efimov. The primary cost for manufacturing the devices would come from the external hardware the device requires.

Mansour said that while such a device would not necessarily increase the life span of a patient beyond what current pacemakers accomplish, it could improve patient quality of life.

“It seems to be a very revolutionary idea. I believe it’s going to be well-received in the field. It targets an unmet need, and I believe it’s going to benefit patients,” said Mansour.

The device could be beneficial for hospitals, Mansour said, given that patients who require a temporary pacemaker are typically roomed in the intensive care unit — valuable real estate in a hospital setting. Because patients with this new device wouldn’t be fixed to a single spot, the ICU could be reserved for patients who need the space more.

He also sees value in the research beyond its initial target. A biodegradable platform could be useful in treating a number of other conditions.

“That’s where the strength of this technology is,” Mansour said, “not only because it targets a temporary patient application, but because of its potential to be expanded to other applications in medicine.”

Source: STAT