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Dutch physiologist, professor and inventor Willem Einthoven performed research and invented concepts for recording electrical heart impulses that greatly evolved the field of cardiology and lead to the development of one of the most important diagnostic tools in all of medicine: the electrocardiogram, or EKG. His adaptation of the string galvanometer made it possible to accurately measure variations in electrical potential caused by heart muscle contractions and to record them graphically.
Einthoven was born on May 21, 1860, in Semarang, on the island of Java, then the Dutch East Indies and now part of Indonesia. There his father served as an army medical officer for the Netherlands. Einthoven lived there until he was ten years old, when his mother, widowed four years before, decided to return to the Netherlands with her six children. The family settled in 1878 in Utrecht.
Einthoven was an avid athlete and astute student, participating in sports such as gymnastics, fencing and rowing. Following in his father's footsteps, he became interested in medicine, studying the subject at the University of Utrecht. His interest veered toward physiology, and he completed his doctoral degree in this field in 1885, producing several remarkable research papers including a study of the human elbow joint, studies on the human eye, and a doctoral thesis on žStereoscopy by means of color variation.Ó
In 1886, Einthoven, after having been certified to serve as a general practitioner, was offered a position as professor of physiology at the University of Leiden. He accepted, and would serve in this post for the rest of his life and career. This position gave him a place to delve into groundbreaking research endeavors in areas of particular interest to him. At first, this included study of the movement of the human eye. He published several papers on the topic. Later, he became keenly interested in the area of respiratory function. His focus turned to electrical phenomena in physiology, mostly as related to the human heart.
At that time, close to the turn of the century, little was known about this subject. Medical study of the heart was very undeveloped, though the concept of electrocardiography had been introduced as early as the 17th century. British physiologist Augustus D. Waller had recorded the first electrocardiogram with a tool called a žcapillary electrometerÓ in 1887. Einthoven conducted an analysis of Waller's work and published a classic paper on the subject. He began registering heart sounds himself using this tool, but quickly realized the instrument's inertia produced errors. He sought a better method.
A string galvanometer had been used earlier for purposes such as amplifying electrical signals over undersea cable. Einthoven thought this technology might also work to measure the tiny electrical variations generated by the heart. In 1901, he completed a model of a string galvanometer using a silver-coated, thin, lightweight quartz string, combining ideas from earlier research done by others in the field. With each current that passes through the string as sent through electrodes attached to a patient, the string would be deflected. The silver coating would make the string opaque, such that when placed in a beam of light, it would throw a shadow onto a plate, where a point of the shadow would shine through to a photographic film and žwriteÓ in a continuous line or curve.
The medical community was impressed with Einthoven's highly sensitive prototype. After his publishing results of the first electrocardiogram using the device in 1902, commercial interest came quickly. The string galvanometer went into production in 1903.
Further improvements and developments followed, pushing the device into mainstream use. In 1905 the first žtelecardiogramÓ was recorded and sent by telephone wire from laboratory to hospital. The following year, Einthoven published a complete presentation of normal and abnormal electrocardiograms recorded with a string galvanometer. He spent several more years studying patterns of records of normal heart activity in order to create a standard for accurately interpreting results.
In 1911, Thomas Lewis published a textbook on the mechanism of the human heartbeat, dedicated to Einthoven. The abbreviation žEKGÓ first appeared in an article in English in 1912. Later developments by scientists including Emanuel Goldberger evolved the standard electrocardiogram that is used today. Einthoven continued to conduct research in this area and other fields until the end of his life.
Einthoven, married and a father to four children, was recognized with a number of honors for his achievements during the course of his career, including membership in the Dutch Royal Academy of Sciences. He was awarded the Nobel Prize for Physiology or Medicine in 1924 for his work in the area of electrical heart properties and the electrocardiograph. He died Sept. 29, 1927 in Leiden, the Netherlands, at the age of 71.