When pacemakers truly became feasible back in the 1970s, there were no batteries really up to the job. Battery life was less than a year. Since replacing the batteries meant heart surgery, this was a problem! Pacemakers powered by Plutonium-238 were developed to give a longer-lived power supply. Note that this is NOT the same type of Plutonium used in a nuclear weapon. The same sort of power supply has been used in some satellites and planetary probes, as well as on the "ALSEP" instrumentation packages left behind on the Moon by our astronauts.
Plutonium powered pacemakers had a very short lifetime of active use. Shortly after they really got going, lithium-ion batteries became available which gave several years of use. This pretty much halted the use of the nuclear-powered pacemakers. Now the overwhelming majority of these (thousands were used worldwide, I don't know a precise figure) are no longer in use, either the patients have passed on, or they have been removed and replaced by something more modern. A handful are still out there, and this one was just removed a couple of weeks ago after being in a patient for 29 years! It was still working perfectly, but the patient needed something this pacemaker couldn't be made to do.
After removal by heart surgeons, it was checked for radioactive contamination (none present!), and shipped away for disposal. I had an opportunity to take a few grab shots with a Rebel XTi and a 24-105mm lens.
Hey a very interesting post here Mike. I did not know anything about pacemakers other than them just being something to keep the old ticker ticking. Thanks for the education. 