A Concise History of the ECG: Difference between revisions

'''1872''' French physicist Gabriel Lippmann invents a capillary electrometer. It is a thin glass tube with a column of mercury beneath sulphuric acid. The mercury meniscus moves with varying electrical potential and is observed through a microscope.

'''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).

'''1872''' 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

'''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.

'''1876''' Marey uses the electrometer to record the electrical activity of an exposed frog's heart. Marey EJ. Des variations electriques des muscles et du couer en particulier etudies au moyen de l'electrometre de M Lippman. Compres Rendus Hebdomadaires des Seances de l'Acadamie des sciences 1876;82:975-977

'''1891''' British physiologists William Bayliss and Edward Starling of University College London improve the capillary electrometer. They connect the terminals to the right hand and to the skin over the apex beat and show a "triphasic variation accompanying (or rather preceding) each beat of the heart". These deflections are later called P, QRS and T. Bayliss WM, Starling EH. On the electrical variations of the heart in man. Proc Phys Soc (14th November) in J Physiol (London) 1891;13:lviii-lix and also On the electromotive phenomena of the mammalian heart. Proc R Soc Lond 1892;50:211-214 They also demonstrate a delay of about 0.13 seconds between atrial stimulation and ventricular depolarisation (later called PR interval). On the electromotive phenomena of the mammalian heart. Proc Phys Soc (21st March) in J Physiol (London) 1891;12:xx-xxi  

==1895 - to date==