Researchers have created an experimental device that powers a pacemaker using only harvested energy from a beating heart.
The technique uses piezoelectricity - electrical charge generated from motion - and could also be used to power other implantable cardiac devices like defibrillators, which also don't need much electricity.
Today's pacemakers must be replaced every five to seven years when their batteries run out.
"Many of the patients are children who live with pacemakers for many years," says M. Amin Karami of the University of Michigan. "You can imagine how many operations they are spared if this new technology is implemented."
Researchers measured heartbeat-induced vibrations in the chest, then used a 'shaker' to reproduce these vibrations in the lab and connected it to their prototype.
Performance measurements, based on sets of 100 simulated heartbeats at various heart rates, showed the energy harvester was able to generate more than 10 times as much power as required.
The next step will be implanting the energy harvester - which is about half the size of current batteries - into a pacemaker for practical testing.
It's not the first time that piezoelectric techniques have been investigated as a way of powering pacemakers. In 2010, a team at Princeton University developed a material that carries out the same function. However, a fair-sized sheet of it, positioned against the lungs, would be necessary to deliver enough power.