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A Concise History of the ECG

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The history of the ECG goes back more than one and a half centurycenturies.
==1600 - 1800==
'''1600.''' William Gilbert, Physician to Queen Elizabeth I, President of the Royal College of Physicians, and creator of the 'magnetic philosophy' , introduces the term 'electrica' for objects (insulators) that hold static electricity. He derived derives the word from the Greek for amber (electra). It was has been known from ancient times that amber when rubbed could lift light materials. Gilbert added adds other examples such as sulphur and was describing describes what would will later be known as 'static electricity' to distinguish it from the more noble magnetic force which he saw . He sees his ideas as part of a philosophy to destroy replace forever the prevailing Aristotlean view of matter. <cite>Gilbert</cite>
'''1649.''' Sir Thomas Browne, Physician, whilst while writing to dispel popular ignorance in many matterssubjects, is the first to use the word 'electricity'. Browne calls the attractive force "Electricity, that is, a power to attract strawes or light bodies, and convert the needle freely placed". (He is also the first to use the word 'computer' - referring to people who compute calendars.)<cite>Browne</cite>
'''1660'''. Otto Von Guericke builds the first static electricity generator.
'''1662'''. The work of Rene Descartes, French Philosopher, is published (after his deathposthumously) and explains human movement in terms of the a complex mechanical interaction of threads, pores, passages and 'animal spirits'. He had has worked on his ideas in the 1630s but had abandoned publication did not publish because of the persecution of other radical thinkers such as Galileo. William Harvey had developed similar ideas but they were never published. <cite>Descartes</cite>
[[Image:Jan_Swammerdam.jpg|thumb|150px|left|Jan Swammerdam]]'''1664'''. Jan Swammerdam, a Dutchman, disproves Descartes' mechanistic theory of animal motion by removing the heart of a living frog and showing that it was the frog is still able to swim. On removing When the brain is removed all movement stopped stops (which would could be in keeping with Descarte's theory) but then, when the frog was is dissected and a severed nerve end stimulated with a scalpel , the muscles twitchedtwitch. This proved proves that movement of a muscle could can occur without any connection to the brain and therefore .Therefore the transmission of 'animal spirits' was is not necessary.
Swammerdam's ideas were are not widely known and his work was is not published until after his death. However, he wrote writes many letters and his friend, Nicolaus Steno, did attack the attacks Cartesian ideas in a lecture in Paris in 1665. Boerhaave published publishes Swammerdam's 'Book of Nature' in the 1730s which was .It is translated into English in 1758.
'''1668''' Swammerdam refines his experiments on muscle contraction and nerve conduction and demonstrated . He demonstrates some of his work to notable figures such as the Grand-Duke Cosimo of Tuscany who was visiting when the Grand Duke visits Swammerdam's father's house on the Oude Schans in Amsterdam. One In one experiment suspended the he suspends a muscle on a brass hook inside a glass tube with a water droplet , to detect movement , and 'irritatedirritates' the nerve with a silver wire. This produced produces movement of the muscle and it , which may have been be due to the induction of a small electrical charge - although Swammerdam would have been is unaware of this.
'''1729''' Stephen Gray, English scientist, distinguishes between conductors and insulators of electricity. He demonstrates the transfer of static electrical charge to a cork ball across 150 metres meters of wet hemp thread. Later he found finds that the transfer could can be achieved over greater distances by using through brass wire.
[[Image:Leyden_Jar.png|thumb|100px|A Leyden Jar]]'''1745''' 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 invents the same device independently.
Using a Leyden jar in 1746, Jean-Antoine Nollet, French physicist and tutor to the Royal royal family of France , sends an electrical current through 180 Royal Guards during a demonstration to for King Louis XV.
'''1769''' Edward Bancroft, an American Scientistscientist, suggests that the 'shock' from the Torpedo Fish torpedo fish is electrical rather than mechanical in nature. He showed shows that the properties of the shock were are similar to those from a Leyden jar in that it could can be conducted or insulated with appropriate materials. The Torpedo torpedo fish and other species were are widely known to deliver shocks and were are often used in this way for therapeutic reasons. However, electrical theory at the this time dictated dictates that electricity would will always flow through conductors and diffuse away from areas of high charge to areas of low charge. Since living tissues were are known to be conductors , it was is impossible to imagine how an imbalance of charge could can exist within an animal and therefore . Therefore animals could can not use electricity for nerve conduction - or to deliver shocks. Furthermore, 'water and electricity do not mix' so the idea of an 'electric fish' was is generally not accepted. <cite>Bancroft</cite>
'''1773''' John Walsh, fellow Fellow of the Royal Society and Member of Parliament, obtains a visible spark from an the electric eel Electrophorus electricus. The eel was is out of water , as it was is not possible to produce the spark otherwise. He used Walsh uses thin strips of tin foil and demonstrated to demonstrate his technique to many colleagues and visitors at his house in London. Unfortunately , he never published publishes his eel experiment , though he did does win the Copley medal in 1774 and 1783 for his work. The Walshes observations of Walsh, and those of Bancroft before him, added adds to the argument that some form of animal electricity existed. <cite>Walsh</cite>
'''1774''' The Rev. Mr Sowdon and Mr Hawes, apothecary, report on the surprising effects of electricity in a case report of recovery from sudden death published in the annual report of the newly founded Humane Society (now the Royal Humane Society). The Society had developed develops from 'The Institution for Affording immediate relief Immediate Relief to persons apparently dead Persons Apparently Dead from drowningDrowning'. It was is "instituted in the year 1774, to protect the industrious from the fatal consequences of unforseen accidents; the young and inexperienced from being sacrificed to their recreations; and the unhappy victims of desponding melancholy and deliberate suicide; from the miserable consequences of self-destruction."
A Mr Squires, of Wardour Street, Soho lived , lives opposite the house from which a three year old girl, Catherine Sophia Greenhill had fallen falls from the a first storey story window on 16th July 1774. After the attending apothecary had declared declares 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 occasioned 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 31-32
'''1775''' Abildgaard shows that hens can be made lifeless with electrical impulses and he could can restore a pulse with electrical shocks across the chest. "With a shock to the head, the animal was rendered lifeless, and arose with a second shock to the chest; however, after the experiment was repeated rather often, the hen was completely stunned, walked with some difficulty, and did not eat for a day and night; then later it was very well and even laid an egg." <cite>Abildgaard</cite>
'''1786''' [[Image:Luigi_Galvani_oil-painting.jpg|thumb|150px|left|Italian Anatomist '''Luigi Galvani''']]Italian Anatomist '''Luigi Galvani''' notes that a dissected frog's leg twitches when touched with a metal scalpel. He had has been studying the effects of electricity on animal tissues that this summer.
[[Image:Galvani_experiment.jpg|thumb|150px|Luigi Galvani's frog leg]]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 shows that direct contact with the electrical generator or the ground through an electrical conductor would lead leads to a muscle contraction. Galvani also used uses 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 notices that the frogs' legs twitched twitch during lightening storms and also when the weather was is fine. He interperated interprets 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 shows 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.
'''1788''' Charles Kite wins the Silver Medal of the Humane Society (awarded at the first Prize Medal prize medal ceremony of the Society , co-judged with the Medical Society of London) with an essay on the use of electricity in the diagnosis and resuscitation of persons apparently dead. This essay is often cited as the first record of cardiac defibrillation , but the use of electricity suggested by Mr Kite is much different. For example, on describing a case of drowning from 1785 where , in which resuscitation had been was attempted with artificial respiration, warmth, tobacco, "volatiles thrown into the stomach, frictions, and various lesser stimuli" for nearly an hour, he then recalls the use of electricity. "Electricity was then applied, and shocks sent through in every possible direction; the muscles through which the fluid [electricity] passed were thrown into strong contractions." He concluded concludes that electricity was is a valuable tool that could can determine whether or not a person, apparently dead, could can be successfully resuscitated. Annual Report 1788: Humane Society, London. pp 225-244. Kite C. An Essay on the Recovery of the Apparently Dead. 1788: C. Dilly, London.
[[Image:Alessandro_Volta.jpg|150px|thumb|left|Alessandro Volta]]'''1792''' 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. [[Image:Voltaic_Pile.jpg|150px|thumb|Voltaic pile]]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: Théorique et expérimental 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
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