Willem Einthoven was born on May 21, 1860 in the city of Semarang on the island of Java in Indonesia. His father was a physician, but died when Willem was only a child. After his father's death, his mother moved back to the Netherlands with young Willem.
In 1870, the family settled in the city of Utrecht, where Willem finished his education. In 1885, he earned a medical degree from the University of Utrecht and was given a position as a professor at the University of Leiden in 1886. When he wasn't teaching, he spent a lot of time researching various medical inventions.
At that time, doctors knew that the heart produced electrical impulses. However, the electronic equipment did not exist to accurately measure the heart rate or view the amplitude of the electrical impulses. In 1901, Einthoven sought to solve this problem using a rather crude method.
Einthoven's method for measuring the waveform of the heart used a "string galvanometer". Essentially it used a thin conductive wire, which ran between two electromagnets. The wire was connected to electrodes on the patient's chest and would move between the electromagnets when a current passed through it (indicating a heartbeat). By shining a light on the wire and placing photographic film underneath the wire, Einthoven was able to record a curve showing the amplitude of the patient's heartbeat.
While Einthoven's machine was very crude, it was able to record the same signal that we see today using modern heart monitors. His machine required five people to run it and weighed in at six hundred pounds. He called it the electrocardiogram (ECG/EKG).
A normal EKG signal
In addition to inventing the machine, Einthoven also named the traditional deflections of a normal ECG waveform, using the letters P, Q, R, S, and T. He also contributed to the medical field by measuring the waveforms produced by various cardiovascular disorders. These irregular rhythms have since become known as arrhythmia and modern devices are able to automatically detect such conditions.
In 1924, Einthoven was awarded the Nobel Prize in Medicine for his invention of the ECG machine. Einthoven died on September 29, 1927 in the city of Leiden.