Not to worry, ain't no more of them.
Back 1975ish there were some installed (afraid I have no idea of the number [a]) in patients because of the issues of standard battery life.
This was a short term program due to a bunch of coinciding issues:
a: huge cost involved b: standard batteries got _much_ better around then, both in regards to power density and life span. Oh, and leakage. c: the Nuclear Regulatory Commission required radiation licensing/certification of a big number of the people involved in the process. In other words, it wasn't like a standard pacemaker which any (competent) medical/surgical/cardiac physician and facmility could install and monitor.
[a] about a decade ago I had a phone conversation with one of the major (well, there are only two or three these days...) pacemaker manufacturing companies. They found one of their real old timers who remembered the deal and gave me the details he recalled.It's just barely, barely, possible there are a handul still in operation. Make that a thimbleful.
It's quite likely that some were buried with their recipient's bodies...
Oh, there was an episode of Emergency [b] where Roy and Johnny had a patient using one.
I don't recall offhand what problems they were concerned with.
[b]