[SoftTalker]

Pu-238 decays mainly by alpha decay which would be easily contained by the titanium casing.

[cyberax]

It also spontaneously fissions, with daughter products often being gamma/beta active. And it always contains some contaminants

[stinkbeetle]

Thanks. Presumably we're talking about "Dose rates at the surface of the pacemaker are approximately 5 to 15 mrem per hour from the emitted gamma rays and neutrons" though.

[SoftTalker]

Yeah ideally I would not want that in or close to my body but if the choice is literally life or death I guess I'll take it.

How do modern pacemakers work? Can they be recharged inductively or is surgery required to replace batteries periodically?