Pacemaker That Runs on Plutonium (1974)

It may seem strange, but in the past there were pacemakers that ran on electricity supplied by small amounts of plutonium inside them. These devices are no longer manufactured, but thanks to their long service life, many were still inside their recipients' chests until 2003. Their solid titanium casing made them practically resistant to any accident.

A Brief History of the Pacemaker

Pacemakers, as they are commonly called, are devices implanted in the patient's body that send regular electrical impulses to the heart muscle to keep it functioning properly. It was Swedish doctors Rune Elmqvist and Ake Senning who designed the first implantable pacemaker in 1958.

Unfortunately, that first device failed within hours of being activated, and it took a couple of years until American engineer Wilson Greatbatch perfected the invention. Greatbatch tested a prototype on a dog, and in 1960, Henry Hannafield, aged 77, became the first human to receive the implant. From that moment on, a race began to make the device as small and durable as possible.

The Battery Problem and Nuclear Power

One of the weak points of these early pacemakers was the short battery life. Placing extra batteries outside the patient's body is quite risky due to the danger of infection from having a couple of wires running out (or in, however you look at it) of the body. In general, you have to make do with the limited space inside the device, which is naturally quite small. Advances made in the 1960s in nuclear batteries based on radioactive materials such as plutonium allowed for the creation of small power sources capable of operating for long periods. Many of these batteries travel through space aboard NASA's robotic probes, and others—as you might have guessed—ended up inside patients with heart problems.

Inside the Plutonium-Powered Pacemaker

The model seen in these photographs uses a thermoelectric battery containing between two and four Curies of plutonium 238, a radioactive material with a half-life of 88 years. These batteries harness the natural decay of plutonium to generate electricity that the pacemaker then sends as pulses to the heart to keep it beating.

To prevent the plutonium radiation from "negatively affecting the patient's health" (or, to put it elegantly, "that it doesn't kill the patient"), everything is sealed inside a titanium box thick enough to stop the gamma rays and neutrons emitted by the battery. This casing is even capable of withstanding bullets and cremation of the patient, something essential to prevent any kind of accident.

Until 2003, between 50 and 100 Americans still carried one of these gadgets inside them, which undoubtedly must have caused interesting commotions every time they tried to pass through an airport security check. As with nuclear weapons or waste from some medical diagnostic equipment that also use radioactive substances, each time one of these patients dies, their pacemaker is sent to the government facilities in Los Alamos to be conveniently recycled. Modern pacemakers have moved away from this type of power source and run on electricity supplied by a lithium battery.

Seen on Implantable Device.