Dr. Karl William Edmark

Dr. Karl William Edmark

Seattle physician Karl William Edmark perfects heart defibrillator between 1959 and 1962.

PhysioControl Timeline

Between 1959 and 1962, Dr. Karl William Edmark (1924?-1994), a cardiovascular surgeon, perfects a heart defibrillator, which Adam Woog describes as “perhaps the most dramatic medical innovation to emerge from the Northwest.” The defibrillator delivers an electrical shock to a fibrillating heart — one that has stopped pumping blood and is in spasm.

The device has a complex history of invention, with several unsatisfactory earlier versions and contributing inventors. Edmark’s key contribution was to make a direct current (rather than alternating current) defibrillator, which was much more effective and much safer.

The defibrillator delivers an electric charge to the heart to get it beating regularly again after its lower two chambers have gone into a twitching spasm that prevents it from pumping blood. If this cannot be stopped, the person dies within three or four minutes.

A subsequent light-weight version was developed by Edmark’s company, Physio-Control, and became an important factor in the development of Medic One, a pioneering rescue unit developed in Seattle in 1970.

In 1998, the firm merged with Medtronic, Inc. and eventually became Medtronic Emergency Response Systems. In 2006 the firm became once again Physio-Control, a division of Medtronic, with plans to separate entirely. It is based in Redmond.