Einthoven's string galvanometer: the first electrocardiograph.

Willem Einthoven (1860--1927), known as the creator of the electrocardiograph, won a Nobel Prize in 1924 for his contributions to the field of electrocardiography. He was dedicated to research and learning. In developing the electrocardiograph, Einthoven built on the work of earlier physiologists who had studied the electrical mechanisms of the heart. Each earlier invention proved important by contributing concepts and knowledge that would shape Einthoven's device. Herein, we review the history of the electrocardiograph, with a focus on Willem Einthoven's quest to make the device a practical clinical instrument in the diagnosis of cardiac abnormalities.