You probably know someone with a heart condition, someone who had a heart attack or even heart surgery. I know I do. According to the Centers for Disease Control, heart disease is the leading cause of death for both men and women in the United States and the most common type of heart disease is coronary artery disease (CAD), which can lead to a heart attack. Sobering data.
There are ways to prevent heart disease such as embracing a healthy lifestyle and there are diagnostic tools to monitor our hearts too, thanks to the work of two creative and persistent men, Norman "Jeff" Holter (1914-1983) and Bruce Del Mar (b. 1913-).
Their collaboration, which spanned two decades, produced a commercially viable heart monitor known as the Holter Monitor Test. The Holter Monitor is a portable device for continuously monitoring heart activity for an extended period of time, typically 24 hours. The monitor records electrical signals from the heart that are sent via a series of electrodes attached to the chest. The data is then analyzed for different sorts of heart beats and rhythms.
Norman "Jeff" Holter, a native of Helena, Montana, was a biophysicist and inventor whose interests were not confined solely to physics. Holter's interest in studying electrical activity in humans during their daily activities without touching them spawned his lifelong pursuit to develop the Holter Monitor. Holter's goal was to radio broadcast and record the more obvious electrophysiological phenomena occurring in humans while carrying on their normal activities, rather than having them be inactive.
Holter's first broadcast of a radioelectrocardiogram (RECG) took place circa 1947 and required 80 to 85 pounds of equipment, which Holter wore on his back while riding a stationary bicycle. Holter noted in 1982 that "The 85 lb. RECG, while not practical, represented a major breakthrough since before that time a patient had to lie quietly. Our greatest contribution was a radical one and was the beginning of an era where one could take ECG's on skiers, parachute jumpers, runners, and just about any other type of vigorous physical activity."
As articles describing the foundation's invention of these devices began to appear in the professional literature, there was considerable demand from doctors and hospitals for the equipment. Holter was seeking a partner to manufacture his monitor, and finally met a suitable candidate in Bruce Del Mar in 1962.
Bruce Del Mar's role as an innovator and collaborator with Holter is especially important because his work spurred the development of an entire diagnostic industry. The Del Mar Avionics Holter Monitor Records, 1951-2011, held at the Archives Center, document through correspondence, engineering notebooks, operator's manuals more than just the invention of a heart monitor. The records reflect the successful collaboration of an independent inventor and a manufacturing firm to problem-solve, develop a solution, and bring to market a diagnostic technology.
The successful collaboration between the two men would prove to be invaluable for countless numbers of people. To learn more about the Holter Monitor story, see the collection finding aid at the Archives Center's web site.
This post also appears on the National Museum of American History's O Say Can You See? blog, an Atlantic partner site.
Images: 1. Norman "Jeff" Holter; 2. Model 445 Mini-Holter Recorder, illustration from a brochure, 1976; 3. Undated cartoon; 4. Advertisement for Del Mar Engineering Laboratories, 1965; 5. Bruce Del Mar.