The problem: a heart that is too slow
The heart’s beat is controlled by electrical signals. In a condition called heart block, the signal that tells the lower chambers to contract is delayed or fails to arrive. The pulse then becomes very slow, and the patient may faint or die. Doctors could recognize the problem on an ECG machine, but before pacemakers they had few options, and a slow heartbeat could be fatal. The idea behind cardiac pacing is to supply a regular electrical pulse that makes the heart beat.
Early external experiments
The notion that electricity could start or steady a heartbeat goes back well before the twentieth century. In 1928 the Australian anesthetist Mark Lidwill, working with the physicist Edgar Booth in Sydney, is reported to have used a device with a needle placed in the heart to revive a newborn. In the early 1930s the American physiologist Albert Hyman described an apparatus using a hand-cranked generator and a needle, and the term “artificial pacemaker” is usually credited to him. These devices were experimental, little used and were met with unease.
Serious clinical pacing began in the early 1950s. Paul Zoll in Boston used an external machine in 1952 that sent pulses through electrodes on the chest, and it kept some patients alive for a time. However, the pulses were painful, caused skin burns, and the machine was plugged into the wall, so a power failure was dangerous.
From wall power to transistors
A key step came in 1957 at the University of Minnesota. After a power cut at a hospital put patients with heart block at risk, the surgeon C. Walton Lillehei asked Earl Bakken, who ran a medical equipment repair business that became Medtronic, to build a battery-powered pacemaker. Bakken built a small transistor-based unit that could be worn on the body, with wires passing through the skin to the heart. The design used electrodes attached directly to the heart and lower voltages, which reduced the pain of the earlier machines. It was an important step, because it showed that the device could be small and portable.
The first implant
The next question was whether the whole thing could be placed inside the body. In Sweden, the physician Rune Elmqvist designed a small device with transistors, sealed in epoxy resin, and the surgeon Åke Senning implanted it in a patient, Arne Larsson, in Stockholm on October 8, 1958. Larsson had severe heart block and his wife pushed for a solution. That first unit is generally reported to have worked for only a short time, and a second was implanted soon afterward. Larsson went on to receive many pacemakers over his life and is reported to have lived into his eighties, long after doctors expected him to die. The details of the first unit’s lifespan vary in accounts, so it is safest to say that it failed quickly.
In the United States, the engineer Wilson Greatbatch and the surgeon William Chardack, working in Buffalo, built a different implantable unit and used it in patients from 1960. Greatbatch is often said to have discovered the circuit idea more or less by accident while building a heart sound recorder and picking the wrong component. His design used mercury-zinc batteries, which gave a useful, though limited, life. The two efforts were independent, and both are part of the story.
Early troubles
The first decade of implanted pacemakers was marked by trial and error. Body fluids seeped into the casings and short-circuited the electronics. Wires snapped as the heart moved. Batteries ran down in a couple of years, which meant repeated surgery. The pulse generators were often fixed-rate, meaning they paced at a constant pace regardless of need and could compete with the patient’s own beat. Better sealing, titanium cases, improved wire insulation and electrode design gradually helped.
Another change was the development of leads that passed through a vein into the heart rather than requiring the chest to be opened, which made implantation far less demanding. Later devices could sense the heart’s own rhythm and pace only when needed, and eventually adjust the rate with activity. Behind these steps were electronics, including the integrated circuits and silicon chips that replaced the first discrete transistors.
Where it led
The pacemaker set a template for later implanted electronics, from the cochlear implant to smart implants that report data about their own performance. It also showed how an implant could be one of many medical instruments that doctors learned to trust only after years of follow-up.
A shared invention
Pacemaker history is a good example of how invention credit can be divided. Hyman and Lidwill preceded the clinical devices, Zoll showed external pacing could work, Bakken and Lillehei made the portable version, Elmqvist and Senning performed the first implant, and Greatbatch and Chardack began the sustained American program. Which one counts as the inventor depends on the definition used.
Power was the main limit on how long implants lasted. That subject is covered in the article on pacemaker batteries, and the later story of shock-delivering devices is told elsewhere in this cluster.
History, not advice
This account is for general interest. Pacemakers today are very different from the early units, and decisions about any heart rhythm treatment are for patients and their physicians.