A Concise History of the ECG: Difference between revisions

'''1788''' Charles Kite wins the Silver Medal of the Humane Society (awarded at the first 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, in which resuscitation 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 concludes that electricity is a valuable tool that can determine whether a person, apparently dead, 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

'''1819''' While demonstrating to students the heating of a platinum wire with electricity from a voltaic pile at the University of Copenhagen, Danish physicist Hans Christian Oersted notices that a nearby magnetized compass needle moves each time the electrical current is turned on. He discovers electromagnetism which is given a theoretical basis (with remarkable speed) by André Marie Ampère.  

'''1820''' Johann (Johan) Schweigger of Nuremberg increases the movement of magnetized needles in electromagnetic fields. He found that by wrapping the electric wire into a coil of 100 turns the effect on the needle was multiplied. He proposed that a magnetic field revolved around a wire carrying a current which was later proven by Michael Faraday. Schweigger had invented the first galvanometer and announced his discovery at the University of Halle on 16th September 1820.  

'''1825''' Leopold Nobili, Professor of Physics at Florence, develops an 'astatic galvanometer'. Using two identical magnetic needles of opposite polarity, either fixed together with a figure of eight arrangment of wire loops (in earlier versions), or one moveable needle with a wire loop and one with a scale (in later versions), the effects of the earth's magnetic field could be compensated for. In 1827, using this instrument, he managed to detect the flow of current in the body of a frog from muscles to spinal cord. He detected the electricity running along saline moistened cotton thread joining the dissected frog's legs in one jar to its body in another jar. Nobili was working to support the theory of animal electricity and this conduction, transmitted without wires, he felt demonstrated animal electricity.  

[[Image:Matteucci.jpg|thumb|150px|left|Carlo Matteucci]]'''1838''' 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). <cite>Matteucci</cite>

'''1840''' Dr Golding Bird, a Physician, accomplished chemist and member of the London Electrical Society, opens an electrical therapy room at Guy's Hospital, London treating a large range of diseases. Although the application of electricity was popular it was not considered a subject worthy of serious investigation. Because of Bird's reputation as a researcher electrical therapy achieved popularity amongst London Physicians including his mentor Dr Thomas Addison. <cite>Bird</cite>

[[Image:Emil_Dubois.jpg|thumb|150px|left|Physiologist Emil Du Bois-Reymond]]'''1843''' 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.

'''1850''' Bizarre unregulated actions of the ventricles (later called ventricular fibrillation) is described by Hoffa during experiments with strong electrical currents across the hearts of dogs and cats. He demonstrated that a single electrical pulse can induce fibrillation. <cite>Hoffa</cite>

'''1856''' Rudolph von Koelliker and Heinrich Muller confirm that an electrical current accompanies each heart beat by applying a galvanometer to the base and apex of an exposed ventricle. They also applied a nerve-muscle preparation, similar to Matteucci's, to the ventricle and observed that a twitch of the muscle occured just prior to ventricular systole and also a much smaller twitch after systole. These twitches would later be recognised as caused by the electrical currents of the QRS and T waves. von Koelliker A, Muller H. Nachweis der negativen Schwankung des Muskelstroms am naturlich sich kontrahierenden Herzen. Verhandlungen der Physikalisch-Medizinischen Gesellschaft in Wurzberg. 1856;6:528-33.  

'''1858''' William thompson (Lord Kelvin), Professor of Natural Philosophy at Glasgow University, invents the 'mirror galvanometer' for the reception of transatlantic telegraph transmissions. A small, freely rotating mirror, with magents stuck to its back is suspended in a fine copper coil and a reflected spot of light from this mirror 'amplifies' the small movements when electrical current is present. The whole apparatus was suspended in an air chamber and the pressure inside could be adjusted to vary the damping seen on the signals. This galvanometer was sensitive enough for transatlantic telegraphy.

'''1867''' Thompson improves telegraph transmissions with the 'Siphon Recorder'. Before d'Arsonval (1880), Thompson uses a fine coil suspended in a strong magnetic magnetic field. Attached to the coil but isolated from it by ebonite (an insulator) was a siphon of ink. The siphon was charged with high voltage so that the ink was sprayed onto the paper that moved over an earthed metal surface. The siphon recorder could therefore not only detect currents it could also record them onto paper.

'''1869-70''' Alexander Muirhead, an electrical engineer and pioneer of telegraphy, may have a recorded a human electrocardiogram at St Bartholomew's Hospital, London but this is disputed. If he had he is thought to have used a Thompson Siphon Recorder. Elizabeth Muirhead, his wife, wrote a book of his life and claimed that he refrained from publishing his own work for fear of misleading others. Elizabeth Muirhead. Alexander Muirhead 1848 - 1920. Oxford, Blackwell: privately printed 1926.

'''1872''' Mr Green, a surgeon, publishes a paper on the resuscitation of a series of patients who had suffered cardiac and / or respiratory arrest during anaesthesia with chloroform. He uses a galvanic pile (battery) of 200 cells generating 300 Volts which he applied to the patient as follows "One pole should be applied to the neck and the other to the lower rib on the left side." Green T. On death from chloroform: its prevention by galvanism. Br Med J 1872 1: 551-3. Although this has been reported as an example of cardiorespiratory resuscitation it is unclear what the exact mechanism seems to be. It is unlikely to be electric cardioversion or external pacing. It seems to be another example of electrophrenic stimulation (See also Duchenne 1872).

'''1875''' Richard Caton, a Liverpool Physician, presents to the British Medical Association in July 1875 in Edinburgh. Using a Thompson 'mirror galvanometer' in animals he shows it was possible to detect 'feeble currents of varying direction ... when the electrodes are placed on two points of the external surface, or one electrode on the grey matter and one on the surface of the skull'. This is the first report of the EEG (or electroencephalogram). Caton was proving another Physician's hypothesis, John Hughlings Jackson, who suggested in 1873 that epilepsy was due to excessive electrical activity in the grey matter of the brain. Caton R: The electric currents of the brain. BMJ 1875; 2:278, Mumenthaler, Mattle Eds. Neurology. 4th Edition. Stuttgart, Thieme: 2004.

[[image:Waller.jpg|thumb|150px|left|A.D. Waller with his famous bulldog Jimmy]]'''1887''' British physiologist Augustus D. Waller of St Mary's Medical School, London publishes the first human electrocardiogram. It is recorded with a capilliary electrometer from Thomas Goswell, a technician in the laboratory. <cite>Waller</cite> This was shortly after the "Cruelty to Animals Act" had been accepted in the British parliament, which lead to questions in the House of Commons.

'''1887''' McWilliam provided the first detailed description of VF, and demonstrated how VF in man could be terminated by electric shocks applied through a large pair of electrodes: the first description of defibrillation in man.<cite>McWilliam1</cite><cite>McWilliam2</cite>

'''1890''' GJ Burch of Oxford devises an arithmetical correction for the observed (sluggish) fluctuations of the electrometer. This allows the true waveform to be seen but only after tedious calculations. <cite>Burch</cite>

Why PQRST and not ABCDE? The four deflections prior to the correction formula were labelled ABCD and the 5 derived deflections were labelled PQRST. The choice of P is a mathematical convention (as used also by Du Bois-Reymond in his galvanometer's 'disturbance curve' 50 years previously) by using letters from the second half of the alphabet. N has other meanings in mathematics and O is used for the origin of the Cartesian coordinates. In fact Einthoven used O ..... X to mark the timeline on his diagrams. P is simply the next letter. A lot of work had been undertaken to reveal the true electrical waveform of the ECG by eliminating the damping effect of the moving parts in the amplifiers and using correction formulae. If you look at the diagram in Einthoven's 1895 paper you will see how close it is to the string galvanometer recordings and the electrocardiograms we see today. The image of the PQRST diagram may have been striking enough to have been adopted by the researchers as a true representation of the underlying form. It would have then been logical to continue the same naming convention when the more advanced string galvanometer started creating electrocardiograms a few years later.  

'''1897''' Clement Ader, a French electrical engineer, reports his amplification system for detecting Morse code signals transmitted along undersea telegraph lines. It was never intended to be used as a galvanometer. Einthoven later quoted Ader's work but seems to have developed his own amplification device independently. <cite>Ader</cite>

'''1899''' Jean-Louis Prevost, Professor of Biochemistry, and Frederic Batelli, Professor of Physiology, both of Geneva discover that large electrical voltages applied across an animal's heart can stop ventricular fibrillation. <cite>Prevost</cite>

'''1901''' Einthoven invents a new galvanometer for producing electrocardiograms using a fine quartz string coated in silver based on ideas by Deprez and d'Arsonval (who used a wire coil). His "string galvanometer" weighs 600 pounds. Einthoven acknowledged the similar system by Ader but later (1909) calculated that his galvanometer was in fact many thousands of times more sensitive. <cite>Einthoven3</cite>

'''1905''' John Hay of Liverpool, publishes pressure recordings from a 65 year old man showing heart block in which AV conduction did not seem to be impaired since the a-c intervals on the jugular venous waves was unchanged in the conducted beats. This is the first demonstration of what we now call Mobitz type II AV block. <cite>Hay</cite>

'''1909''' Thomas Lewis of University College Hospital, London buys a string galvanometer and so does Alfred Cohn of Mt Sinae Hospital, New York. Thomas Lewis publishes a paper in the BMJ detailing his careful clinical and electrocardiographic observations of atrial fibrillation. At one point Lewis identified a fibrillating horse using the string galvanometer's electrocardigram recording. He then followed the horse to the slaughterhouse where he could visually confirm the fibrillating atrium. <cite>Lewis</cite>

'''1910''' Walter James, Columbia University and Horatio Williams, Cornell University Medical College, New York publish the first American review of electrocardiography. It describes ventricular hypertrophy, atrial and ventricular ectopics, atrial fibrillation and ventricular fibrillation. The recordings were sent from the wards to the electrocardiogram room by a system of cables. There is a great picture of a patient having an electrocardiogram recorded with the caption "The electrodes in use".James WB, Williams HB. The electrocardiogram in clinical medicine. Am J Med Sci 1910;140:408-421, 644-669

'''1911''' Levy & Lewis demonstrated that when VF occurred during chloroform anesthesia, it was often preceded by the appearance of multiform ventricular premature beats or ventricular tachycardia.<cite>Lewis</cite>

'''1912''' Einthoven addresses the Chelsea Clinical Society in London and describes an equilateral triangle formed by his standard leads I, II and III later called 'Einthoven's triangle'. This is the first reference in an English article I have seen to the abbreviation 'EKG'.Einthoven W. The different forms of the human electrocardiogram and their signification. Lancet 1912(1):853-861  

'''1920''' Hubert Mann of the Cardiographic Laboratory, Mount Sinai Hospital, describes the derivation of a 'monocardiogram' later to be called 'vectorcardiogram'. <cite>Mann</cite>

'''1926''' A doctor from the Crown Street Women's Hospital in Sydney, who wished to remain anonymous, resuscitates a new-born baby with an electrical device later called a 'pacemaker'. The doctor wanted to remain anoymous because of the controversy surrounding research that artificially extended human life.  

'''1928''' Ernstine and Levine report the use of vacuum-tubes to amplify the electrocardiogram instead of the mechanical amplification of the string galvanometer. <cite>Ernstine</cite>  

'''1929''' Sydney doctor Mark Lidwill, physician, and Edgar Booth, physicist, report the electrical resuscitation of the heart to a meeting in Sydney. Their portable device uses an electrode on the skin and a transthoracic catheter. Edgar Booth's design could deliver a variable voltage and rate and was employed to deliver 16 volts to the ventricles of a stillborn infant.  

[[image:White_stamp.gif|thumb|150px|left|Dr. Paul Dudley White]]'''1930''' Wolff, Parkinson and White report an electrocardiographic syndrome of short PR interval, wide QRS and paroxysmal tachycardias. Wolff L, Parkinson J, White PD. Bundle branch block with short P-R interval in healthy young people prone to paroxysmal tachycardia. Am Heart J 1930;5:685. Later, when other published case reports were examined for evidence of pre-excitation, examples of 'Wolff Parkinson White' syndrome were identified which had not been recognised as a clinical entity at the time. The earliest example was published by Hoffmann in 1909. Von Knorre GH. The earliest published electrocardiogram showing ventricular preexcitation. Pacing Clin Electrophysiol. 2005 Mar;28(3):228-30

'''1931''' Charles Wolferth and Francis Wood describe the use of exercise to provoke attacks of angina pectoris. They investigated the ECG changes in normal subjects and those with angina but dismissed the technique as too dangerous "to induce anginal attacks indiscriminately". <cite>Wood</cite>

'''1931''' 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. <cite>Hyman</cite>

'''1935''' McGinn and White describe the changes to the electrocardiogram during acute pulmonary embolism including the S1 Q3 T3 pattern. <cite>McGinn</cite>  

'''1938''' American Heart Association and the Cardiac Society of Great Britain define the standard positions, and wiring, of the chest leads V1 - V6. The 'V' stands for voltage. Barnes AR, Pardee HEB, White PD. et al. Standardization of precordial leads. Am Heart J 1938;15:235-239  

'''1942''' Arthur Master, standardises the two step exercise test (now known as the Master two-step) for cardiac function. Master AM, Friedman R, Dack S. The electrocardiogram after standard exercise as a functional test of the heart. Am Heart J. 1942;24:777  

'''1947''' Gouaux and Ashman describe an observation that helps differentiate aberrant conduction from ventricular tachycardia. The 'Ashman phenomenon' occurs when a stimulus falls during the relative or absolute refractory period of the ventricles and the aberrancy is more pronounced. In atrial fibrillation with aberrant conduction this is demonstrated when the broader complexes are seen terminating a relatively short cycle that follows a relatively long one. The QRS terminating the shorter cycle is conducted 'more aberrantly' because it falls in the refractory period. The aberrancy is usually of a RBBB pattern. <cite>Gouaux</cite>