History of Medicine

WILLEM EINTHOVEN AND THE FIRST

ELECTROCARDIOGRAMS

     Is there electricity in heart muscle?  No one knew until, by accident, two German scientists, Köllicker and Müller, in 1856, saw that when the end of a frog’s sciatic nerve was mistakenly laid on top of a living frog’s heart, every heartbeat caused a twitch in muscle attached to the nerve. In subsequent years the anatomic pathways conducting current through the heart were mapped out, laying the groundwork for further study.

     The knowledge was fascinating, but could a recording of the feeble electrical activity help people with heart disorders? Yes, as it turned out.    

     The first recording in a human appears to have been done by Alexander Muirhead at St. Bartholomew’s Hospital in 1869 or 1870. He used something called a Thompson siphon recorder, an instrument made to record telegraph messages and based on movements of a wire coil between two magnets. Muirhead left medicine, however, to become a telegraph engineer. Next was

Auguste Waller (Wellcome Library)

Auguste Waller, son of Augustus Waller, who discovered “Wallerian degeneration” (degeneration of a nerve fiber distal to the site of injury). Waller placed a capillary electrometer, a thin, capillary-like tube enclosing a column of mercury topped by sulfuric acid, on the human chest. The electricity of the heart passed through the tube, moving the mercury level up and down, the motion recorded by strong light passing through a magnifier to a moving film. Response time was slow and the recordings not very sensitive. (See figure 1) Waller did not foresee much clinical use for his device.

Waller's Mercury Column Tracings
Fig 1: Lower tracing is EKG, middle one is chest wall vibrations from heart beat,
and upper one counts time (From J Physiol 1887; 8: 229-34, Hathi Trust))

     For the transition to modern electrocardiography we owe thanks to a Dutchman, Willem Einthoven. Einthoven was born in 1860 in the Dutch East Indies, where his father was a military physician. He was educated in Holland after his father died and

Willem Einthoven (Wellcome Library)

received his medical degree at the University of Utrecht. With the help of his professor of physiology, Franz Donders (who made important advances in ophthalmology), Einthoven became professor of physiology at Leiden University in 1886, at age 26. Stimulated by Donders, he began to record electric currents from the human heart, employing the same mercury column used by Waller. Einthoven, however, was also a self-taught mathematician and devised formulas to extrapolate the sluggish EKG pattern into a more readable and remarkably accurate form. (See figure 2)

Fig 2. Upper tracing by Einthoven is from mercury column. Lower one is derived mathematically
from the upper, with PQRST labelling applied (from Arch ges Phys 1885; 60:101-23, Hathi Trust))

He also changed the lettering of the deflections to PQRST from the ABCD used by Waller, apparently following a mathematical convention for labeling curved forms. He experimented with leads placed in various combinations, ending up with the 3 conventional leads used today. The leads were obtained by submerging a hand or foot in a jar of electrolyte solution.

     Einthoven’s lab was located in an old building adjacent to a cobblestone street. Vibrations from horse-drawn wagons passing by outside frustrated his work with the electrometer. Digging a hole 10-15 feet deep and fortifying it with rocks did not help.

      As a way out, Einthoven took advantage of a new instrument invented by a Frenchman, Clement Ader, called a string galvanometer. Ader placed a thin metal wire, 20 microns thick, between 2 magnets, to record wiggles as a tiny current passed through. This ingenious man had devised the first stereo apparatus and gave the first stereo renditions of the Paris Opera. He also was the first to fly a motorized plane, uncontrolled (the Wright brothers' was controlled), and later wrote a popular book on aviation.

     Einthoven took the galvanometer a step further, using a string of only 2.1 micron diameter. The string was made by placing a piece of quartz on the rear end of an arrow attached to a crossbow.

Schematic of Einthoven's string galvanometer. String is vertically
placed between 2 magnets. A microscope and light pass through
horizontally to project onto film (Einthoven, 1906, Hathi
Trust))

The quartz was heated to near-liquid state and the arrow fired. The thin, floating, thread left behind was coated delicately with silver before use. Using a strong arc light, a 600-power magnifier, and sensitive rolling film, Einthoven recorded amazingly accurate tracings. They corresponded well to the renditions he had calculated from the coarse mercury tube records. Einthoven called his recordings “electrokardiograms”, soon 

Lead one EKG, string galvanometer, published 1906 (Einthoven, 1906, Hathi Trust)
The high quality is remarkable

shortened to “EKG”. Before long he was able to publish on various rhythm disturbances, including heart block, atrial fibrillation, and the like (see Figure). 

Atrioventricular block (Einthoven, 1906, Hathi Trust)

     Einthoven’s apparatus was so large it could not be transported to a hospital, but the Cambridge Scientific Instrument Company learned how to manufacture a moveable version. One of the company’s founders, Horace Darwin, youngest son of Charles Darwin, negotiated with Einthoven to put galvanometers on the market, giving Einthoven a percentage of the sales. Clinical

Subject with hands in jars of electrolyte
solution as leads (Einthoven, 1906, Hathi Trust)

electrocardiography was born.  

     For his discoveries Einthoven was awarded the Nobel Prize in 1924, a prize worth $40,000 dollars at the time. Feeling that he could not have won the prize without the help of his now-retired lab assistant, Van der Woerd, Einthoven wished to share the prize. He found that the former assistant had died but was survived by 2 sisters, living frugally in an almshouse. Einthoven awarded half of his prize to the sisters.

     When the Queen of Holland learned of Einthoven’s award she offered to replace his old building with a new, modern structure with a fine laboratory. Einthoven declined the building, asking instead for money to hire another assistant and purchase new research equipment. The Queen obliged.

     Einthoven was described as a generous, graceful, man of simple tastes, who spoke 3 languages, and was instrumental in maintaining good international scientific relations over the years, not an easy task through the World War One period. His contribution to cardiology speaks for itself.

SOURCES

Cooper, J. “Electrocardiography 100 Years Ago”. NEJM 1986; 315: 461-4.

Ershler, I. “Einthoven – The Man”. Arch Int Med 1988; 148: 453-5.

Burnett, J. “The Origins of the Electrocardiograph as a Clinical Instrument” Medical History Suppl 5, 1985; 53-76.

Waller, A. “A Demonstration on Man of Electromotive Changes Accompanying the Heart’s Beat”. J Physiol 1887; 8: 229-34.

Einthoven, W. “Über die Form des Menschlichen Electrocardiogramms”. Arch gesamte Physiol 1895; 60:101-23.

Einthoven, W. “Über das Normale Menschliche Electrokardiogramm und über die capillar-electrometrische Untersuchung Einige Herzkranken” Arch gesamte Physiol 1900; 80: 139-60.

Einthoven, W. “Über das Normale Menschliche Electrokardiogramm und über die capillar-electrometrische Untersuchung Einige Herzkranken” Arch gesamte Physiol 1900; 80: 139-60.

Acierno, L J. The History of Cardiology. 1994; Parthenon Publishing.