Holter, Norman Jefferis (1914–1983),
American biophysicist. Holter made his first notable contribution during World War II, when, as senior physicist for the United States Navy's Bureau of Ships, he conducted important research on the behavior of ocean waves. After the war he and his staff of oceanographic engineers measured wave action and underwater disturbances caused by the atomic testing at the South Pacific atoll of Bikini. During 1952 he recorded for the Atomic Energy Commission the fallout caused by the atmospheric testing of the hydrogen bomb. His later researches ranged from seismography to vitamin C. In medicine he was notable for his work on electrocardiography and his invention of a portable apparatus for monitoring heart activity. Originally known as an ambulatory electrocardiograph, the device is now associated with his name.