So far, work has been limited to animals and human heart tissue studied in the laboratory. But experts said the early findings were “exciting” and could potentially change the care of patients who need a pacemaker for just days to weeks.
Pacemakers are devices implanted to help control certain abnormal heart rhythms by sending electrical impulses to the heart muscle.
Traditional permanent pacemakers consist of a battery-powered pulse generator that is implanted under the skin of the chest and connected to the heart by wires called leads.
But sometimes patients only need stimulation for a short time, such as after a cardiac procedure that leaves them with a slow heartbeat. In this case, an external pulse generator is used, but patients should still have electrodes sewn onto the heart, fitted with wires that come out of the chest and connect to the generator.
While pacemakers work well, there is a risk that drivers will become dislodged or cause infection, said John Rogers, a professor at Northwestern University in Chicago, who led the development of the “dissolving” pacemaker.
The thin, flexible device has no wires or batteries, and its materials biodegrade within weeks.
So the technology could be well suited for patients who need a temporary pacemaker, Rogers said.
A heart rhythm specialist who was not involved in the research agreed.
“This is an exciting proof-of-concept study,” said Dr. Rachel Lampert, member of the electrophysiology section and board of directors of the American College of Cardiology.
“We would like to have a temporary absorbable pacemaker,” Lampert said, referring to the device’s ability to dissolve in bodily fluids.
While the prospect seems worrying, Rogers said the pacemaker components include materials already used in sutures, as well as “minute amounts” of substances in the body, such as iron, magnesium and silicon.
The apparatus, which weighs less than half a gram, has an encapsulating layer which contains electrodes; the bottom of each electrode is exposed and adheres to the surface of the heart. It connects wirelessly to an external antenna, using the same technology that enables smartphones to make contactless payments, Rogers explained.
At this point, the pacemaker has been tested in several animal models, as described in the report published on June 28 in the journal Natural biotechnology.
Before moving on to human testing, Rogers said researchers want to know more about what happens to biodegradable materials when they dissolve. For example, is it possible for a small piece to get lodged in a blood vessel?
The dissolving process, explained Rogers, “does not occur uniformly. It will generate small fragments. We have to see where these fragments go before they completely resorb.”
As it stands, Rogers said the technology would translate into a specific scenario: patients undergoing open chest surgery who need temporary stimulation while in hospital. The device must be placed by open surgery, and it would be activated and controlled by a healthcare professional via the remote antenna.
Lampert noted that there is already a permanent wireless pacemaker that doctors can implant through a catheter – a thin tube that is threaded through a vein to reach the heart without open surgery.
If this temporary device could be implanted this way, Lampert said, it could open it up to more uses, such as when patients need temporary stimulation. after a heart attack or a catheter procedure.
Rogers said his team is working on this possibility.
The researchers also want to develop the biodegradable technology for other medical uses, he added. An example would be for patients who temporarily need a peripheral nerve stimulator – an implant that can help relieve pain after surgery or injury.
As for potential costs, the biodegradable approach could save money, according to Rogers, since it bypasses the need for surgical extraction.