Willem Einthoven

Dutch physiologist

• Born: May 21, 1860
• Birthplace: Semarang, Java, Dutch East Indies (now Indonesia)
• Died: September 28, 1927
• Place of death: Leiden, the Netherlands

Accomplished in several areas of physiology, physics, and medicine, Einthoven elaborated techniques for measuring minute electrical currents in the human heart. His string galvanometer best known in its later form as an electrocardiogram, or EKG became the basis for modern electrocardiography and made possible great advances in combating heart disease. He was awarded the Nobel Prize in Physiology or Medicine in 1924.

Early Life

There are few published details concerning the early life of Willem Einthoven (VIHL-ehm INT-hoh-vehn). He was born in Semarang, Java, the Dutch East Indies (now the Republic of Indonesia), the son of a Jewish doctor who served there as the municipal physician. When Willem was six, his father died, and four years later his mother, Louise de Vogel, left Semarang with her six children to settle among relatives in the homeland city of Utrecht, the Netherlands, where Willem received most of his early education.

On his graduation from high school in 1879, Einthoven immediately registered as a medical student at the University of Utrecht. Trim, athletic and an active sportsman, he made a wrist that he had broken in a fall the occasion for his initial medical publication. Produced in 1882, it was a study on rotations of the hand and forearm (pronation and supination) and articulation of the elbow.

A superb medical student, Einthoven was also blessed with unusually capable teachers whom he remembered fondly throughout life. Although he worked closely with the physicist Buys Ballot and with the anatomist Willem Koster, his most intensive study and experimentation came under the tutelage of Dutch ophthalmologist Hermann Snellen, whom he assisted in the medical school clinic as well as in Snellen’s private practice, and under the distinguished physiologist-ophthalmologist Franciscus Cornelius Donders. Between 1858 and 1864, Donders had variously discovered major causes of farsightedness and of astigmatism, and it was under Donders’s direction that Einthoven received his Ph.D. in medicine cum laude in 1885, his dissertation having been written on stereoscopy (the study of three-dimensional sight) through color differentiation.

With medical school behind him, Einthoven married his cousin, Frédérique Jeanne Louise de Vogel (with whom he eventually had three children), and prepared to settle vigorously at the age of twenty-five into his new professorship in physiology and histology at the University of Leiden a post he occupied until his death.

Life’s Work

Einthoven’s research and writing, viewed over the full span of his career, were catholic in their breadth. His dissertation aside, he variously published results of his investigations on the physiology of the bronchial musculature, on the physiology of the eye, on the physiology of the nasal passages and the larynx, as well as on the physics of the capillary electrometer and the law of nerve energies. Thus, although his professional training had been in medicine, he revealed himself to be as much the physicist as the doctor or physiologist. Moreover, because he understood the history both of physiology and of physics, he clearly perceived their areas of interrelation and acted on those perceptions.

Temperamentally fastidious, meticulous, and rarely satisfied that experiments, or their results, could not be improved on, Einthoven early in his career seized on the inadequacies of the electrocardiogram and the imprecision of the electrometer as central curiosities. In 1886, in fact, shortly after receiving his medical degree, he had won considerable recognition for his discoveries about the electrical characteristics of nerve energies discoveries that were largely responsible for his being offered his University of Leiden professorship. Discerning and measuring electrical energies by movement of a magnetic needle or by a coil in a magnetic field, whether, as was true in Einthoven’s case, by employment of an electrocardiogram or by employment of a capillary electrometer, meant essentially that he was dealing with galvanometers.

Galvanometers were nothing new to Einthoven’s age. Using the Dane Hans Christian rsted’s discovery of electromagnetism in 1820, German physicist and chemist Johann Schweigger immediately plunged into the rapidly developing field of electrodynamics, devising the first galvanometer that same year. Improvements followed, albeit slowly, and by 1843, England’s Charles Wheatstone had devised a sensitive instrument for measuring electrical resistance (soon called the Wheatstone bridge) and the shunt, which permitted galvanometers to measure large electrical currents. The galvanometer with which Einthoven was most familiar had been developed in 1880 by the Frenchman Jacques-Arsène d’Arsonval. It was the modification of d’Arsonval’s instrument the Deprez-d’Arsonval mirror galvanometer which, however valuable, was neither sufficiently sensitive nor swift enough for Einthoven’s purposes, to which he dedicated himself to improving drastically, the better to serve physiological research. Those improvements, in time, would bring Einthoven his widest renown and highest encomiums.

Einthoven, in one of his papers, has provided the history of the development of his famous string galvanometer, a device that he soon named the electrocardiogram. The basic problem that he sought to resolve had been posed by Augustus Volney Waller, a London physiologist. Ever since the experiments of the Bolognese anatomist Luigi Galvani in the late eighteenth century, scientists generally knew that living bodies possessed electric potentials and currents. Waller, for his part, had published the curve for the heart’s action current as he deduced it from the body’s surface but declared his inability to calculate the curve’s actual shape as defined by a capillary electrometer. Considering a direct registration of the heart curve’s true configuration a medical necessity, Einthoven repeated Waller’s experiment, defining the physical constants of the capillary electrometer and eventually calculating the curve’s true shape. The chief product of this process, by 1896, was his then still rudimentary electrocardiogram and requisite photographic equipment.

The magnitude, complexity, and delicacy of these developments were immense. Having commenced research on the basis of the Deprez-d’Arsonval galvanometer, Einthoven soon discovered that reductions in the number of its moving coils increased its sensitivity, maximal sensitivity being obtained with only a single winding of very fine wire. Simultaneously to ensure the greatest possible clarity in an electrocardiogram’s measurements, he managed by 1903 to establish the instrument’s coordinates (the ordinate and abscissa) at one centimeter movement for the ordinate for each millivolt tension difference and a shutter speed of twenty-five millimeters per second so that one centimeter of the abscissa represented four-tenths of a second. These became standard measurements for general use. Brilliantly eclectic, he then borrowed the chief principle employed in Clément Ader’s device for measuring submarine signals, an instrument consisting of a long, single wire placed vertically between a magnet’s poles. Over the next twenty years of experimentation, by greatly increasing the strength of the magnetic field and by introducing very short, thin, light fibers, as well as by developing an optical projection system of very high magnification, time signals, and recording cameras, he created an apparatus of unprecedented accuracy and sensitivity: his so-called string galvanometer. Records from this instrument directly represented in curvilinear form alterations in current from instant to instant. Its representations, unlike recordings made by the capillary electrometer, required no analysis, making it ideal for clinical observations.

In two papers published respectively in 1906 and 1908, Einthoven directed attention to major dispositions that could be made of his apparatus even as it existed then. His special emphasis was on its utility in portraying electrical events in the human heart, thereby establishing records of its health or pathology. Adapting separate leads, pairing the three sets of adjacent angles of a rough equilateral triangle, and theoretically calculating the line of the heart’s electrical axis from the resultant curves, he opened use of his instrument not only to physiology but also to the entire medical world. In so doing, he was the seminal influence in the founding of modern human and experimental electrocardiography.

His published papers further illuminate his pioneering work in electrophysiology. Between 1913 and 1923, having devised and then refined an electrophonic circuit, he was able not only to measure the heart’s beat at any phase of its cycle but also to monitor its pathology, that is, record the flutters and fibrillations of its auricles. The electrical characteristics of other organs also solicited his curiosity and by 1923 he had invented methods for the measurement of currents conveyed by the vagus nerve from the heart to the lungs and brain. At the request of medical colleagues, he successfully measured currents in the somatic nerve and muscle as well as in the sense organs, secretory glands, and the cervical sympathetic nerve.

By the early 1920’s, thousands of Einthoven’s string galvanometers, or electrocardiograms, manufactured commercially by the Edelman Company and by the Cambridge and Paul Instrument Company, had become standard equipment in major medical facilities, providing basic weaponry in the diagnosis and treatment of heart and neural disorders. For the corpus of his work, Einthoven became the recipient of many honors: selection as a foreign fellow of the Royal Society; honorary membership in the Physiological Society; first of the Edward K. Dunham lecturers at the Harvard University Medical School; and, in 1924, recipient of the Nobel Prize in Physiology or Medicine. After several years of failing health, Einthoven died on September 28, 1927, in Leiden, the Netherlands.

Significance

In his prime, a warm, hospitable, engaging man, replete with a full beard and piercing eyes, Einthoven was a highly civilized and accomplished person, fluent in several languages, deeply read, and diverse in his interests. Although preoccupied with his string galvanometer and attendant experiments in electrophysiology, he built an instrument at Leiden that received weak radio signals from his birthplace, the Dutch East Indies, and that, with modifications, could also track the velocities of artillery shells and consequently locate enemy guns. Apparently none of his inventions, whether or not commercially built, brought him significant wealth, and, while comfortable, he lived modestly.

His years of almost compulsive experimentation (during his later years in collaboration with his son, an electrical engineer) with variants of his galvanometer, and its ancillary recording and photographic equipment, are best characterized as a triumph of methodology. His instrumentation was exquisite, establishing new standards and meanings for the terms “accuracy” and “sensitivity.” For example, he could record potential changes of frequencies of the order of 100,000 per second. He reduced errors in his galvanometer’s time measurements of physiological electric curves to such minute intervals as 0.0001 or 0.00001 of a second. As early as 1909, his galvanometer was 100,000 times more sensitive than any in existence. Constantly refining his work, he discovered how to draw the galvanometer’s lengthy “strings,” or fibers, to remarkable thinness; that is, his quartz threads were drawn to between two and three millionths of an inch in diameter, capable of responding to sound variations of a frequency of 150,000 per second. The movements of these fibers were captured photographically by Einthoven.

Modern electrocardiology and electrophysiology are literally founded on Einthoven’s painstaking endeavors and achievements, and the broader realms of cardiology and physiology have both been revolutionized by them. Moreover, without seeking to profit personally, he moved as swiftly as he could at all stages of his experimentation to suggest practical applications of his discoveries and instrumentation. In so doing, he brilliantly illustrated how intimate connections sometimes can be between university professorships and laboratories and the well-being of the workaday world.

Bibliography

Barron, S. L. Willem Einthoven: Biographical Notes. Cambridge, England: Cambridge University Press, 1952. English-language materials, indeed writings in any language, on Einthoven are notable for their scarcity, so this monograph is particularly welcome. An extensive treatment of his life and work; clear, nontechnical, and authoritative.

Einthoven, Willem. “The Relation of Mechanical and Electrical Phenomena of Muscular Contraction, with Special Reference to the Cardiac Muscle.” In The Harvey Lectures. Philadelphia: J. B. Lippincott, 1924-1925. The subject matter treated here was central to Einthoven’s lifelong investigations and, while technical, is nevertheless clearly stated. Nonspecialists should have no difficulty understanding his major points.

Hill, Leonard. “Obituary. Prof. Willem Einthoven.” Nature 120 (1927): 591-592. Given the dearth of English-language appreciations of Einthoven’s life and work, this authoritative overview of his career is very useful. Happily, too, this distinguished journal, in which so many new scientific writings have first appeared, is readily available in most large public and university libraries. While Einthoven was little known to the general public that he quietly served so well, it gives some indication of the esteem in which he was held by the world’s scientific community.

Lewis, T. L. “Willem Einthoven.” Heart 14 (August, 1928): 5-8. Concentrating on Einthoven’s methodology, this clearly written, authoritative summation by another major physiologist is extremely useful. Despite its brevity, it contains excellent specifics about Einthoven’s experimental achievements.

Nobel Foundation. “Willem Einthoven.” In Nobel Lectures: Physiology or Medicine, 1922-1941, vol. 2. New York: Elsevier, 1965. This article contains a fairly in-depth, though brief, biography of Einthoven, his Nobel Prize acceptance speech, and the Nobel committee’s statement on Einthoven’s contributions.

Snellen, Herman A. William Einthoven (1860-1927): Father of Electrocardiography Life and Work, Ancestors and Contemporaries. Reprint. New York: Springer, 2003. Provides an understanding of Einthoven’s life, work, and relation to his contemporaries in the medical profession.