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University alumnus Earl Bakken holds his revolutionary invention: the first wearable cardiac pacemaker. Around his neck is the Russ Medal for outstanding achievement, awarded by the National Academy of Engineering.
When alumnus Earl Bakken invented a wearable pacemaker, he sparked a revolution
When alumnus Earl Bakken invented a wearable pacemaker, he sparked a revolution in medicine
By Deane Morrison
December 21, 2007
October 1957 is remembered as the start of the Space Age, but that month also witnessed the birth of a new era in medicine. As the Soviet satellite Sputnik sailed overhead, a power blackout in Minneapolis led University alumnus Earl Bakken to invent a tiny metal box that sparked a revolution: the first wearable cardiac pacemaker. Earlier this month Bakken, an electrical engineer who graduated in 1948, received the first honorary Doctor of Medicine degree from the University in recognition of his contributions. Last week, at a symposium in his honor, he recounted the tale of the pacemaker's genesis. The blackout on Halloween 1957 left a legendary University heart surgeon, C. Walton Lillehei, with a tiny patient who needed electricity to stay alive. Lillehei had repaired a hole in the baby's heart, but the electrical signals that control the heartbeat had been blocked. An AC-powered stimulator was standing in for the heart's natural rhythm until the child's heart could recover. The stimulator plugged into wall sockets, limiting patients and doctors alike. "It was hard when you had to move a patient," Bakken recalls. "You had to run extension cords, sometimes down an elevator." Whether the baby survived or not (memories differ on that point), it was clear to Lillehei that there had to be a better way. So the next time he ran into Bakken, who was already in the business of fixing and calibrating medical equipment, he asked if Bakken couldn't rig a battery to back up the stimulator. Bakken was then working out of a cramped, kerosene-heated garage with business partner Palmer Hermundslie, his wife's sister's husband. Eight years earlier, in that same space, they had created a company called Medtronic. When Lillehei made his request, Bakken first envisioned a cart loaded with a battery, charger, and inverter--all the necessities for running an AC-powered pacemaker. Then another idea struck.
"I remembered a two-transistor circuit for a metronome. I plagiarized the circuit and built a pacemaker. ... Then I walked in the hospital one day and saw it connected to a child.""I remembered a two-transistor circuit for a metronome," Bakken says. "I plagiarized the circuit and built a pacemaker." Four weeks later, Bakken brought Lillehei a transistorized, battery-powered pacemaker housed in an aluminum circuit box about the size of a slice of bread. A trial on a research animal was successful, and Bakken assumed many more such trials would be performed. "Then I walked in the hospital one day and saw it connected to a child," he says. The device was strapped to patients' chests and was connected to two electrodes: one surgically placed in contact with heart muscle and the other implanted under the skin. The external box had an on/off switch, plus knobs for controlling the stimulus rate and strength. Sure enough, young patients started playing with the knobs, so the first commercial models of the pacemaker had recessed, kid-proof knobs. "It was a great experience, saving the lives of kids," Bakken muses. The invention allowed the University to lead the way in short-term pacing of the heart, keeping patients alive until their hearts recovered normal function--usually about two or three weeks. Then the electrodes could be pulled out. Soon, both Medtronic and pacemaker technology started to take off. In 1959 a Medtronic engineer named Norman Roth teamed up with Samuel Hunter, a surgeon at St. Joseph's Hospital in St. Paul, to design a new pacemaker lead that combined both electrodes inside a plastic patch that could be stitched to the heart. This more permanent pacemaker was first used on a patient, Warren Mauston of St. Paul, in April 1959. Mauston lived with it for more than seven years. The first successful implantable pacemaker also came along in 1959, the creation of Wilson Greatbatch of the University of Buffalo and William Chardack, chief of thoracic surgery at the Buffalo Veterans Administration Hospital. It was first used in 1960, and in 1966 Medtronic bought the associated patents. The rest is history. Medtronic has been phenomenally successful; the company now sells medical devices all over the world and reported revenues of $12.3 billion for the year ending April 29, 2007. Among the many spinoff companies founded by Medtronic employees is St. Jude Medical, famous for its mechanical heart valve. Pacemakers have shrunk to the size of two silver dollars stacked atop each other, and more than 400,000 are implanted every year. In 1984 the pacemaker was named one of the 10 outstanding engineering achievements of the second half of the 20th century by the National Society of Professional Engineers. In 2001 Bakken and Greatbatch were recognized with the $500,000 Fritz J. and Dolores H. Russ Prize from the National Academy of Engineering and Ohio University. The prize recognizes achievements that improve the quality of life and have attained wide application or use. Today, visitors to the Bakken Museum, sitting on the western shore of Lake Calhoun in Minneapolis, can trace the history of electricity in medicine and hear the life story of the museum's founder and namesake. Its executive director, David Rhees, says he always gets a charge out of watching children tour the museum. "One of them is going to be the next Earl Bakken," he predicts.