The Pacemaker was an accident that actually saves lives today. Wilson Greatbatch was working on a device to record irregular heartbeats when he accidentally inserted a resistor of the wrong size. He noticed that the circuit pulsed, stopped, and pulsed again–just like a human heart.  He worked with it for about two years and eventually made the first implantable pacemaker.

Before the implantable pacemaker was invented, people with irregular heartbeats had to control their pulse using a sometimes painful external device invented in 1952 by Paul Zoll. The external pacemaker was about the size of a small television, and administered life-saving jolts of electricity, which sometimes burned the skin.

Greatbatch later invented a corrosion-free lithium battery to power the pacemaker.