I found this (PDF), doesn't mention current use, though.
about their history and actual use (paywall)
not recent...
I suggest you talk to your cardiologist. I can't quickly find any doc on this -- even through googling-- , but it may not be publicly available. From the few docs I can find, I think that they have been deemed safe for medical use but with the improvements of li-ion tech, possibly inductive charging, and other technologies, the use of rtg for pacemaker would look less attractive nowadays, not even considering the risks of accidental release of radioactive material (cremation...)...
So, ask your specialist, or his professors :-)

mod parent up!
I've also wondered why the hybrids still had direct heat engine to wheels transmission.

mod parent up

Well, as an european, I can give you a few things that make us better off with Europe, the Euro and all that... We can now live and work in any European country without permit or visa. 30 years ago, trying to do that would have meant months of dealing with the administration of both countries. We can now enjoy the end of speculative games that broke the weakest currencies of smaller countries every 5 years or so in the 80ies. We benefit from Europe-wide quality standards in foods, poollution levels, drugs and so on that are better than about anywhere, and enforced efficiently. We have strong (though not well enforced yet) privacy laws. We have strong anti-monopolistic laws that succeeded at condemning Microsoft for abusive practices, and Intel recently..

Well, we should be able to do them in for tax evasion, then, shouldn't we?

I've heard somewhere that it was linked to earth tides . Wikipedia's references here and here (pdf). They apparently modify the geometry of the ring slightly..