Between 1966 and 1972, many heart pacemaker implants used radioactive Plutonium-238 embedded in the device as a power source. So-called Nuclear-Powered Cardiac Pacemakers could maintain continuous power for over 40 years. :
A HEART IS GIVEN ATOM PACEMAKER - The New York Times
MedTech Memoirs: The Plutonium-Powered Pacemaker - Medical Design and Outsourcing
The History of Nuclear Powered Pacemakers
9 Nuclear Heart Pacemakers Implanted - The New York Times
The Rise and Fall of the Nuclear Pacemaker
A nuclear-powered cardiac pacemaker? Yes, but…. (Part 1) - Power Electronic Tips
Nuclear Batteries – The World of Implantable Devices
Nuclear Batteries with Potential
How Medtronic fit a battery into a tiny pacemaker - Medical Design and Outsourcing
Are Radioactive Diamond Batteries a Cure for Nuclear Waste? | WIRED
Teeny Tiny Pacemaker Fits Inside the Heart - IEEE Spectrum
Russian scientists pack more power into nuclear battery prototype
Nuclear Batteries with Potential
Tiny Nuclear Pacemaker For the Heart Developed - The New York Times
Implanted generator could use ultrasound to charge pacemaker batteries
Nuclear Diamond Battery Will Run For 28,000 Years: NDB Facts
Physics - Wireless Power for Tiny Medical Devices
Pacemakers may go nuclear | UK | News | Express.co.uk
Nuclear powered cameras? Enter the diamond battery!
New Pacemaker Technologies for the Heart
Researchers debut battery-less pacemaker
Micromachines | Free Full-Text | The Miniaturization of Cardiac Implantable Electronic Devices: Advances in Diagnostic and Therapeutic Modalities