Willem_Einthoven--John_James_Richard_Macleod

Willem Einthoven (21 May 1860 – 29 September 1927) was a Dutch medical doctor and physiologist. He invented the first practical electrocardiograph (ECG or EKG) in 1895 and received the Nobel Prize in Physiology or Medicine in 1924 for it ("for the discovery of the mechanism of the electrocardiogram").