One of the big downfalls of the pacemaker (apart from their newly discovered vulnerability to hacking) is that every couple of years you have to open up a person again in order to install a new set of batteries. So why not tap the body to power this device directly?
A paper being presented at the American Heart Association's Scientific Sessions 2012 proposes just that — tapping into the rhythmic movements of the heart to power the lifesaving devices. A pacemaker actually requires only a very small amount power to do its thing, which is why they tend to last five to seven years between replacements - and the body is more than capable of producing enough energy to do so.
Study author M. Amin Karami of the the Department of Aerospace Engineering at the University of Michigan in Ann Arbor has developed a pizoelectric energy harvester that should be capable of powering a pacemaker. Using a shaker to reproduce the level of vibrations seen in the heart, his team reproduced 100 simulated heartbeats at various rates — and harvested ten times the amount of power required to keep the pacemaker going.
By using a nonlinear harvester, Karami was able to still gather power regardless of the active heart rate of the patient, and with a device half the size of a current pacemaker battery pack. While it does sound a bit bizarre to power something using the same organ it's meant to keep functioning, anything to significantly reduce the number of procedures someone with a pacemaker has to go through seems like a win in my book.