Wilson Greatbatch, credited with inventing the implantable pacemaker in 1958, died earlier this week at the age of 92, his family said.
As a young electrical engineering professor at the State University of New York at Buffalo he had been working on a heart rhythm monitor when he accidentally stumbled on a way to generate precisely timed electric pulses.
He quit his job to work full-time on developing a device small enough to fit inside a person's chest.
Key to the design was the transistor, which was just coming into mass production in the late 1950s to replace bulky vacuum tubes in electronic devices.
"Once the transistor was readily available, I knew I could make an implantable pacemaker," he wrote in a 2003 essay.
A prototype device was successfully tested in dogs at the Veterans Administration hospital in Buffalo in 1958. Two years later, the first human implants were performed there.
The design was subsequently licensed to Medtronic, which had developed an external, wearable pacemaker a few years earlier.
Although a team at Sweden's Karolinska Institute had implanted their own pacemaker device into a patient in 1958, it did not run long enough to be considered practical.
Greatbatch also helped solve one of the biggest problems with early pacemakers, including his own -- the two-year life of the mercury-zinc batteries that were used initially. (The first recipient of the Swedish pacemaker reportedly had a total of 20 replacements before he died in 2001.)
In 1972, Greatbatch came up with a lithium battery that could last 10 years. It became the workhorse for many medical devices in addition to pacemakers.
According to the New York Times, Greatbatch held more than 325 patents on a wide variety of devices.
He remained active well into his 80s. Among his most recent interests was the prospect for power generation from helium fusion.
He was a member of the National Academy of Engineering and was inducted into the Inventors Hall of Fame in 1986.
In 2003, the academy cited the Greatbatch device as one of the greatest engineering achievements of the 20th century.