What do you get when you combine a heart surgeon and an electrical engineer?
December 1957. As snow swirls around a garage-turned workshop in northeast Minneapolis, the young man inside hunches over a collection of wires, resistors, switches, and other electrical bits and pieces. History is being made: The man is Earl Bakken, and the device taking shape in his hands is the world’s first wearable transistorized pacemaker. By summer, his invention will be keeping young children alive after open-heart surgery. By 2007, the device and others based on it will have given millions of individuals around the world a new chance to lead healthy lives.
“The invention of the implantable pacemaker has extended the lives and improved the quality of life of uncountable numbers of children and adults,” says David Benditt, M.D., cardiology professor and codirector of the University’s Cardiac Arrhythmia Center. “It has clearly benefited mankind to a greater extent than any other single medical technology.”
The device has “revolutionized cardiovascular medicine,” agrees Lillehei Heart Institute director Daniel Garry, M.D., Ph.D., holder of the St. Jude Medical Cardiovascular Chair in Biomedical Engineering and director of the Department of Medicine’s Cardiology Division. “And it has given rise to a number of new inventions that have been applied increasingly not only to heart-rhythm abnormalities but to heart failure as well.”
The original device, which gave rise to the dual-chamber pacemaker, then to the biventricular pacemaker, has also contributed to the development of implantable cardioverter defibrillators, which are used today to monitor for and automatically correct abnormal rhythms in individuals with prior heart problems.
This cascade of innovation all started with a conversation between Bakken and University of Minnesota open-heart surgery pioneer C. Walton Lillehei, M.D., Ph.D. (Medical School Class of 1941), a half-century ago. Sometimes after Lillehei operated on a child to fix a congenital heart defect, the child’s heart would temporarily lose its ability to keep a regular beat. Lillehei’s solution was to connect such patients to an electrical device that delivered regular pulses.
But this AC-powered pacemaker was bulky—about the size of a microwave oven—and had to be plugged into a wall outlet connected to a central electrical-supply system.
After a power failure at the University’s hospital on October 31, 1957, drove home the precariousness of depending on an external source of electricity, Lillehei asked Bakken, an electrical engineering alumnus who helped maintain equipment at the hospital, to try to come up with something better.
Bakken’s first instinct was to put a car battery on a cart and use it to drive the big pulse-delivering machine. Then he remembered an article he had seen in Popular Electronics describing how to build a compact metronome using a tiny battery and transistors. Working from the metronome directions, Bakken wired and soldered together a portable pacemaker. Powered by a tiny 9-volt battery, this smaller device—about the size of a peanut butter sandwich—could deliver just the right jolt to healing hearts.
When the transistorized pacemaker was ready, Bakken took it to the hospital’s research lab to try it on a dog. To his delight, it seemed to do the job.
The day after, when Bakken stopped by, he was astounded to see that Lillehei had already attached the device to one of his patients.
By the end of 1958, Bakken’s garage-based company, Medtronic, had received orders for five dozen of the devices. In the 50 years since, Medtronic, Inc., has become a global leader in the medical device industry, and more than 2 million pacemakers have been used to keep hearts and their owners going strong.