library contents | ECG axis | ECG history | ECGs by Example
Find out how electrocuting chickens (1775), getting laboratory assistants to put their hands in buckets of saline (1887), taking the ECG of a horses and then observing their open heart surgey (1912), induction of indiscriminate angina attacks (1931), and hypothermic dogs (1953) have helped to improve our understanding of the ECG as a clinical tool. And why is the ECG labelled PQRST (1895)?
17th and 18th Centuries | The harnessing of electricity, observations of its effects on animal tissues and the discovery of 'animal electricity'. |
William Gilbert | William Gilbert, Physician to Queen Elizabeth I, President of the College of Physicians (before its Royal Charter), and creator of the 'magnetic philosophy' introduces the term 'electrica' for objects (insulators) that hold static electricity. He derived the word from the Greek for amber (electra). It was known from ancient times that amber when rubbed could lift light materials. Gilbert added other examples such as sulphur and was describing what would later be known as 'static electricity' to distinguish it from the more noble magnetic force which he saw as part of a philosophy to destroy forever the prevailing Aristotlean view of matter. Gilbert W. De Magnete, magneticisique corporibus, et de magno magnete tellure. [On the Magnet, Magnetic Bodies, and the Great Magnet of the Earth] 1600 |
Descarte's reflex ©BIU | The work of Rene Descartes, French Philosopher, is published (after his death) and explains human movement in terms of the complex mechanical interaction of threads, pores, passages and 'animal spirits'. He had worked on his ideas in the 1630s but had abandoned publication because of the persecution of other radical thinkers such as Galileo. William Harvey had developed similar ideas but they were never published. Descartes R. De Homine (Treatise of Man); 1662: Moyardum & leffen, Leiden. |
Swammerdam's ideas were not widely known and his work was not published until after his death. However, he wrote many letters and his friend, Nicolaus Steno, did attack the Cartesian ideas in a lecture in Paris in 1665. Boerhaave published Swammerdam's 'Book of Nature' in the 1730s which was translated into English in 1758.
electrical stimulation? ©BIU | Swammerdam refines his experiments on muscle contraction and nerve conduction and demonstrated some to notable figures such as the Grand-Duke Cosimo of Tuscany who was visiting Swammerdam's father's house on the Oude Schans in Amsterdam.
One experiment suspended the muscle on a brass hook inside a glass tube with a water droplet to detect movement and 'irritated' the nerve with a silver wire.
This produced movement of the muscle and it may have been due to the induction of a small electrical charge - although Swammerdam would have been unaware of this.
In the diagram opposite - a) glass tube, b) muscle, c) sliver wire, d) brass wire, e) drop of water, f) investigator's hand. |
Leyden Jar | Dutch physicist Pieter van Musschenbroek discovers that a partly filled jar with a nail projecting from a cork in its neck can store an electrical charge.
The jar is named the 'Leyden Jar' after the place of its discovery. Ewald Georg von Kliest of Pomerania invented the same device independently.
Using a Leyden jar in 1746, Jean-Antoine Nollet, French physicist and tutor to the Royal family of France sends an electrical current through 180 Royal Guards during a demonstration to King Louis XV. |
John Walsh | John Walsh, fellow of the Royal Society and Member of Parliament, obtains a visible spark from an electric eel Electrophorus electricus. The eel was out of water as it was not possible to produce the spark otherwise. He used thin strips of tin foil and demonstrated his technique to many colleagues and visitors at his house in London. Unfortunately he never published his eel experiment though he did win the Copley medal in 1774 and 1783 for his work. The observations of Walsh, and Bancroft before him, added to the argument that some form of animal electricity existed. Walsh, J. On the electric property of torpedo: in a letter to Ben. Franklin. Phil. Trans. Royal Soc. 1773;63:478-489 |
A Mr Squires, of Wardour Street, Soho lived opposite the house from which a three year old girl, Catherine Sophia Greenhill had fallen from the first storey window on 16th July 1774. After the attending apothecary had declared that nothing could be done for the child Mr Squires, "with the consent of the parents very humanely tried the effects of electricity. At least twenty minutes had elapsed before he could apply the shock, which he gave to various parts of the body without any apparent success; but at length, upon transmitting a few shocks through the thorax, he perceived a small pulsation: soon after the child began to sigh, and to breathe, though with great difficulty. In about ten minutes she vomited: a kind of stupor, occaisioned by the depression of the cranium, remained for some days, but proper means being used, the child was restored to perfect health and spirits in about a week.
"Mr. Squires gave this astonishing case of recovery to the above gentlemen, from no other motive than a desire of promoting the good of mankind; and hopes for the future that no person will be given up for dead, till various means have been used for their recovery."
Since it is clear she sustained a head injury the electricity probably stimulated the child out of deep coma rather than providing cardiac defibrillation (see also 1788, Charles Kite). Annual Report 1774: Humane Society, London. pp 31-32Luigi Galvani | Italian Anatomist Luigi Galvani notes that a dissected frog's leg twitches when touched with a metal scalpel. He had been studying the effects of electricity on animal tissues that summer.
On 20th September 1786 he wrote "I had dissected and prepared a frog in the usual way and while I was attending to something else I laid it on a table on which stood an electrical machine at some distance from its conductor and separated from it by a considerable space. Now when one of the persons present touched accidentally and lightly the inner crural nerves of the frog with the point of a scalpel, all the muscles of the legs seemed to contract again and again as if they were affected by powerful cramps." He later showed that direct contact with the electrical generator or the ground through an electrical conductor would lead to a muscle contraction. Galvani also used brass hooks that attached to the frog's spinal cord and were suspended from an iron railing in a part of his garden. He noticed that the frogs' legs twitched during lightening storms and also when the weather was fine. He interperated these results in terms of "animal electricity" or the preservation in the animal of "nerveo-electrical fluid" similar to that of an electric eel. He later also showed that electrical stimulation of a frog's heart leads to cardiac muscular contraction. Galvani. De viribus Electritatis in motu musculari Commentarius. 1791 Galvani's name is given to the 'galvanometer' which is an instrument for measuring (and recording) electricity - this is essentially what an ECG is; a sensitive galvanometer. |
Alessandro Volta | Alessandro Volta, Italian Scientist and inventor, attempts to disprove Galvani's theory of "animal electricity'" by showing that the electrical current is generated by the combination of two dissimilar metals. His assertion was that the electrical current came from the metals and not the animal tissues. (We now know that both Galvani and Volta were right.) To prove his theory he develops the voltaic pile in 1800 (a column of alternating metal discs - zinc with copper or silver - separated by paperboard soaked in saline) which can deliver a substantial and steady current of electricity. Enthusiasm in the use of electricity leads to further attempts at reanimation of the dead with experiments on recently hanged criminals. Giovani Aldini (the nephew of Galvani) conducts an experiment at the Royal College of Surgeons in London in 1803. The executed criminal had lain in a temperature of 30 F for one hour and was transported to the College. "On applying the conductors to the ear and to the rectum, such violent muscular contractions were executed, as almost to give the appearance of the reanimation". Aldini, J. Essai: Th�orique et exp�rimental sur le Galvanisme, Paris (1804), Giovani Aldini. General Views on the Application of Galvanism to Medical Purposes Principally in cases of suspended Animation (London: J. Callow, Princes Street and Burgess and Hill, Great Windmill Street, 1819). Mary Shelly's Frankenstein was published in 1818. Louis Figuier, Les merveilles de la Science (Paris, 1867), p.653 |
1800 to 1895 | The design of sensitive instruments that could detect the small electrical currents in the heart. |
Carlo Matteucci | Carlo Matteucci, Professor of Physics at the University of Pisa, and student of Nobili, shows that an electric current accompanies each heart beat. He used a preparation known as a 'rheoscopic frog' in which the cut nerve of a frog's leg was used as the electical sensor and twitching of the muscle was used as the visual sign of electrical activity. He also used Nobili's astatic galvanometer for the study of electricity in muscles typically inserting one galvanometer wire in the open end of the dissected muscle and the other on the surface of the muscle. He went on to try and demonstrate conduction in nerve but was unable to do so (since his galvanometers were not sensitive enough). Matteucci C. Sur un phenomene physiologique produit par les muscles en contraction. Ann Chim Phys 1842;6:339-341 |
Emil Du bois-Reymond | German physiologist Emil Du bois-Reymond describes an "action potential" accompanying each muscular contraction. He detected the small voltage potential present in resting muscle and noted that this diminished with contraction of the muscle. To accomplish this he had developed one of the most sensitive galvanometers of his time. His device had a wire coil with over 24,000 turns - 5 km of wire. Du Bios Reymond devised a notation for his galvanometer which he called the 'disturbance curve'. "o" was the stable equilibrium point of the astatic galvanometer needle and p, q, r and s (and also k and h) were other points in its deflection. Du Bois-Reymond, E. Untersuchungen uber thierische Elektricitat. Reimer, Berlin: 1848. |
An 'electric' smile. | Guillaume Benjamin Amand Duchenne de Boulogne, pioneering neurophysiologist, describes the resuscitation of a drowned girl with electricity in the third edition of his textbook on the medical uses of electricity. This episode has sometimes been described as the first 'artificial pacemaker' but he used an electrical current to induce electrophrenic rather than myocardial stimulation. Duchenne GB. De l'electrisation localisee et de son application a la pathologie et la therapeutique par courants induits at par courants galvaniques interrompus et continus. [Localised electricity and its application to pathology and therapy by means of induced and galvanic currents, interrupted and continuous] 3ed. Paris. JB Bailliere et fils; 1872 |
1895 to date | The first accurate recording of the electrocardiogram and its development as a clinical tool. |
Karel Wenkebach | Karel Frederik Wenckebach publishes a paper "On the analysis of irregular pulses" describing impairment of AV conduction leading to progressive lengthening and blockage of AV conduction in frogs. This will later be called Wenckebach block (Mobitz type I) or Wenckebach phenomenon. |
first patented pacemaker | Dr Albert Hyman patents the first 'artificial cardiac pacemaker' which stimulates the heart by using a transthoracic needle. His aim was to produce a device that was small enough to fit in a doctor's bag and stimulate the right atrial area of the heart with a suitably insulated needle. His experiments were on animals. His original machine was powered by a crankshaft (it was later prototyped by a German company but was never successful). "By March 1, 1932 the artificial pacemaker had been used about 43 times, with a successful outcome in 14 cases." It was not until 1942 that a report of its successful short term use in Stokes-Adams attacks was presented. Hyman AS. Resuscitation of the stopped heart by intracardial therapy. Arch Intern Med. 1932;50:283 |
modern 'Holter' Monitor | Montana physician Norman Jeff Holter develops a 75 pound backpack that can record the ECG of the wearer and transmit the signal. His system, the Holter Monitor, is later greatly reduced in size, combined with tape / digital recording and used to record ambulatory ECGs. Holter NJ, Generelli JA. Remote recording of physiologic data by radio. Rocky Mountain Med J. 1949;747-751. |
long QT syndrome | Anton Jervell and Fred Lange-Nielsen of Oslo describe an autosomal recessive syndrome of long-QT interval, deafness and sudden death later known as the Jervell-Lange-Nielsen syndrome. Jervell A, Lange-Nielsen F. Congenital deaf mutism, functional heart disease with prolongation of the QT interval and sudden death. Am Heart J 1957;54:59. |
Excercise ECG | Robert Bruce and colleages describe their multistage treadmill exercise test later known as the Bruce Protocol.
"You would never buy a used car without taking it out for a drive and seeing how the engine performed while it was running," Bruce says, "and the same is true for evaluating the function of the heart."
Bruce RA, Blackman JR, Jones JW, Srait G. Exercise testing in adult normal subjects and cardiac patients. Pediatrics 1963;32:742 Bruce RA, McDonough JR. Stress testing in screening for cardiovascular disease. Bull. N.Y. Acad Med. 1969;45:1288 |
Torsade de pointes | Fran�ois Dessertenne of Paris publishes the first case of 'Torsade de pointes' Ventricular Tachycardia. Dessertenne F. La tachycardie ventriculaire a deux foyers opposes variables. Arch des Mal du Coeur 1966; 59:263 |
Comments, corrections or additions are very welcome.