How was Willem Einthoven awarded the Noble Prize in Physiology or Medicine?

Name: Willem Einthoven.
Country: Netherlands.
Date of Birth: 21 May 1860.
Died: 29 September 1927.
Education: University of Utrecht.
Subjects Of Study: Bioelectric Potential Heart.
Known as: First practical electrocardiogram machine, Clinical electrocardiography Einthoven’s triangle.
Noble Prize Year: Nobel Prize for Peace in 1924, for the discovery of the mechanism of the electrocardiogram.