In 1956, Wilson Greatbatch — an engineer at the University of Buffalo — was building an oscillator to record heart sounds. He reached into a box of resistors, pulled the wrong one (a 1-megohm instead of a 10-kilohm), soldered it in, and switched the circuit on. Instead of recording a heartbeat, the device produced one: a rhythmic 1.8-millisecond pulse, 60 times a minute. Greatbatch froze. He had spent years listening to cardiologists complain about "Stokes-Adams" patients whose hearts stopped in sudden, fatal blocks. He was looking at the solution.

Six years later, on July 22, 1960, he filed US Patent 3,057,356 — "Medical Cardiac Pacemaker" — granted October 9, 1962. The patent describes a transistorized pulse generator, sealed in epoxy, with two electrodes stitched directly to the heart muscle. It ran on ten mercury-zinc cells and drew about 8 microamps between pulses. It was small enough (roughly the size of a hockey puck) to bury under a patient's skin.

This was radical. Every prior "pacemaker" was a bedside cart the size of a television, tethered to the patient by wires through the chest wall. Paul Zoll's 1952 external device required chest-wall electrodes so painful that patients begged doctors to shut it off. Åke Senning's 1958 Swedish implant lasted three hours before failing. Greatbatch's insight was mundane and profound: use a blocking oscillator — a simple transistor circuit that spends 99% of its time in a low-power off state, waking only long enough to fire a millisecond pulse. Duty cycle, not efficiency, was the whole game.

The first human implant, at Buffalo's Millard Fillmore Hospital in April 1960, kept a 77-year-old man alive for 18 months. Greatbatch licensed the patent to Medtronic — then a garage-scale medical repair shop in Minneapolis — for a handshake and a modest royalty. Medtronic sold 50 units in the first year. Today it is a $130 billion company, and roughly 3 million people worldwide walk around with a descendant of Greatbatch's circuit humming under their collarbone.

The modern relevance is direct and startling:

• Every implantable medical device — cochlear implants, deep-brain stimulators for Parkinson's, vagus nerve stimulators for epilepsy, spinal cord stimulators, insulin pumps, and now Neuralink-style brain-computer interfaces — follows Greatbatch's architecture: hermetic case, low-duty-cycle circuit, direct-to-tissue electrode.
• The lithium-iodide battery Greatbatch invented in 1970 to replace the mercury cells (leaky, short-lived) is still the standard chemistry for pacemakers 55 years later — a rare case of a technology that hasn't been dislodged.
• The "wake, pulse, sleep" pattern he pioneered is now the fundamental power-management model for every battery-sipping IoT device, LoRa sensor, and wearable on Earth. Your Apple Watch's ECG feature and a modern pacemaker share more design DNA than either shares with a 1970s desktop computer.
• The FDA's entire "Class III implanted device" regulatory pathway was built around Greatbatch's device — it is the ancestor of the rules governing every neural implant filed in 2026.

Greatbatch died in 2011, holding 325 patents. He once said the wrong resistor was "the most productive mistake I ever made." It bought roughly 60 million patient-years of extra life — and drafted the blueprint for a body full of quiet, listening machines.