[allisvancity]

They evidently used to use radiothermal generators (RTGs) as the power source for some pacemakers.

https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_ge...

Plutonium is nasty & expensive stuff, however. That puts some pretty severe limitations on its usefulness for domestic purposes.

[1letterunixname]

RTGs in humans: not for a long time.