An experimental pacemaker operated without a conventional battery by directly harvesting the energy produced by heartbeats.
A pacemaker sends small electrical impulses when the heart rhythm needs to be corrected. Wireless models implanted directly in the heart avoid the long wires used by traditional devices. However, their small size requires a compact battery, whose lifespan eventually limits that of the device.
Pixabay illustration
Pengfei Chen’s team and colleagues therefore integrated a tiny generator into the pacemaker. With each heartbeat, the movement of the heart activates internal components. The contact and separation of different materials then produce electrical charges. This principle is known as triboelectric generation.
In practical terms, the heart provides the movement and the device converts it into electricity. The generator reaches a power density of 276.6 microwatts per cubic centimeter under the conditions reported by the researchers. The harvested energy then powers the electronics responsible for producing the stimulation impulses.
The system was designed in a form compatible with an intracardiac pacemaker, meaning one placed inside the heart. This approach preserves the advantage of wireless devices while eliminating their dependence on a chemical energy reserve that gradually runs out.
The researchers then evaluated their prototype in pigs, whose hearts allow preclinical testing close to the conditions encountered in humans. The device provided cardiac stimulation during a one-month follow-up. This duration demonstrates its short-term operation, but not yet use over several years.
A pacemaker intended for a patient must operate reliably despite variations in heart rate, movement, and material aging. It must also remain safe in contact with tissue.
The next step is to verify its durability over much longer periods and in a wider range of physiological situations. Ultimately, the researchers aim to develop a self-sustaining pacemaker that can remain in place without surgery prompted solely by depletion of its energy source.