History of Cardiac Pacing

In 1954 Dr. C. Walton Lillehei, a cardiac surgeon at the University of Minnesota, made advances in the treatment of the blue baby syndrome. In blue baby syndrome there is an abnormal blood communication between the left and right chambers of the heart. As a part of the treatment, Lillehei typically closed holes in the septum between the left and right heart chambers. Because the normal conduction system is in this septum, one common complication of the surgery was complete heart blockage, which meant the patient had no pulse. This heart blockage often resolved over a period of weeks, but to keep the child alive until then, Lillehei used temporary epicardial pacing. These pacing pads were sewn onto the heart and power by a large cart-mounted electrical generator. The patients were effectively tethered to the wall plug. If nurses had to move them, the staff could walk only so far as the next electrical outlet, unplug the generator, and then replug it into the next outlet. This not only made it difficult for the patients to be active, it made it difficult to move them for tests. This system, while cumbersome, allowed Lillehei to keep many children alive, and by 1957 he was one of the busiest congenital cardiac surgeons in the nation.

On October 31, 1957, a 3-hour power outage in Minneapolis rendered these generators useless because the wards had no backup electrical generators. Although one version of the story is that a child died, in an interview with Earl Bakken, Lillehei reported no deaths. Nonetheless, Lillehei knew he needed something battery operated.¹ Soon after this, Lillehei contacted Bakken, an engineer who owned the Medtronic medical equipment service company. Bakken spent the next month working on a pacemaker generator that would be small enough to wear and be powered by batteries. As inspiration he used an electronic, transistor-based metronome that generated sound periodically.