Editing Electrocardiography (section)

==History==
[[File:Willem Einthoven ECG.jpg|thumb|An early commercial ECG device (1911)]]
[[File:BASA-532K-1-2-15-Ran Bosilek.jpg|thumb|ECG from 1957]]
* In 1872, [[Alexander Muirhead]] is reported to have attached wires to the wrist of a patient with fever to obtain an electronic record of their heartbeat.<ref>{{Cite ODNB |doi=10.1093/ref:odnb/37794 |title=Muirhead, Alexander (1848–1920), electrical engineer |last=Birse |first=Ronald M }}</ref>
* In 1882, [[John Burdon-Sanderson]] working with frogs, was the first to appreciate that the interval between variations in potential was not electrically quiescent and coined the term "isoelectric interval" for this period.<ref>{{Cite journal |last=Rogers |first=Mark C. |date=1969 |title=Historical Annotation: Sir John Scott Burdon-Sanderson (1828-1905) A Pioneer in Electrophysiology |journal=Circulation |volume=40 |issue=1 |pages=1–2 |doi=10.1161/01.CIR.40.1.1 |pmid=4893441 |doi-access=free }}</ref>
* In 1887, [[Augustus Desiré Waller|Augustus Waller]]<ref name="Waller_1887">{{Cite journal |last=Waller AD |year=1887 |title=A demonstration on man of electromotive changes accompanying the heart's beat |journal=J Physiol |volume=8 |issue=5 |pages=229–34 |doi=10.1113/jphysiol.1887.sp000257 |pmc=1485094 |pmid=16991463}}</ref> invented an ECG machine consisting of a [[lippmann electrometer|Lippmann capillary electrometer]] fixed to a projector. The trace from the heartbeat was projected onto a photographic plate that was itself fixed to a toy train. This allowed a heartbeat to be recorded in real time.
* In 1895, [[Willem Einthoven]] assigned the letters P, Q, R, S, and T to the deflections in the theoretical waveform he created using equations which corrected the actual waveform obtained by the capillary electrometer to compensate for the imprecision of that instrument. Using letters different from A, B, C, and D (the letters used for the capillary electrometer's waveform) facilitated comparison when the uncorrected and corrected lines were drawn on the same graph.<ref name=naming/> Einthoven probably chose the initial letter P to follow the example set by [[Descartes]] in [[geometry]].<ref name=naming/> When a more precise waveform was obtained using the string galvanometer, which matched the corrected capillary electrometer waveform, he continued to use the letters P, Q, R, S, and T,<ref name="naming">{{Cite journal |last=Hurst JW |date=3 November 1998 |title=Naming of the Waves in the ECG, With a Brief Account of Their Genesis |journal=Circulation |volume=98 |issue=18 |pages=1937–42 |doi=10.1161/01.CIR.98.18.1937 |pmid=9799216|doi-access=free }}</ref> and these letters are still in use today. Einthoven also described the electrocardiographic features of a number of cardiovascular disorders.
* In 1897, the string galvanometer was invented by the French engineer [[Clément Ader]].<ref>{{Cite journal |last=Interwoven W |year=1901 |title=Un nouveau galvanometre |journal=Arch Neerl Sc Ex Nat |volume=6 |page=625}}</ref>
* In 1901, Einthoven, working in [[Leiden]], the [[Netherlands]], used the [[string galvanometer]]: the first practical ECG.<ref>{{Cite journal |vauthors=Rivera-Ruiz M, Cajavilca C, Varon J |date=29 September 1927 |title=Einthoven's String Galvanometer: The First Electrocardiograph |journal=Texas Heart Institute Journal  |volume=35 |issue=2 |pages=174–78 |pmc=2435435 |pmid=18612490}}</ref> This device was much more sensitive than the capillary electrometer Waller used.
* In 1924, Einthoven was awarded the [[Nobel Prize in Medicine]] for his pioneering work in developing the ECG.<ref name="Cooper_1986">{{Cite journal |last=Cooper JK |year=1986 |title=Electrocardiography 100 years ago. Origins, pioneers, and contributors |journal=N Engl J Med |volume=315 |issue=7 |pages=461–64 |doi=10.1056/NEJM198608143150721 |pmid=3526152}}</ref>
* By 1927, General Electric had developed a portable apparatus that could produce electrocardiograms without the use of the string galvanometer. This device instead combined amplifier tubes similar to those used in a radio with an internal lamp and a moving mirror that directed the tracing of the electric pulses onto film.<ref>{{Cite journal |last=Blackford, John M., MD |date=1 May 1927 |title=Electrocardiography: A Short Talk Before the Staff of the Hospital |journal=Clinics of the Virginia Mason Hospital |volume=6 |issue=1 |pages=28–34}}</ref>
* In 1937, [[Taro Takemi]] invented a new portable electrocardiograph machine.<ref>{{Cite news |url=https://www.hsph.harvard.edu/takemi/about-the-program/dr-taro-takemi/ |title=Dr. Taro Takemi |date=2012-08-27 |work=Takemi Program in International Health |access-date=2017-10-21 |language=en-US}}</ref>
* In 1942, Emanuel Goldberger increases the voltage of Wilson's unipolar leads by 50% and creates the augmented limb leads aVR, aVL and aVF. When added to Einthoven's three limb leads and the six chest leads we arrive at the 12-lead electrocardiogram that is used today.<ref name="nicehist">{{Cite web |year=2009 |title=A (not so) brief history of electrocardiography. |url=https://ecglibrary.com/ecghist.html}}</ref>
* In the late 1940s, [[Rune Elmqvist]] invented an inkjet printer involving thin jets of ink deflected by electrical potentials from the heart, with good frequency response and direct recording of ECG on paper. The device, called the Mingograf, was sold by Siemens Elema until the 1990s.<ref>{{cite web
  | title = A (not so) brief history of electrocardiography
  | publisher = ECG Library
  | date = 2006-01-03
  | url = https://www.ecglibrary.com/ecghist.html
  | doi =
  | accessdate = 2021-01-11
  | archive-date = 2012-02-02
  | archive-url = https://web.archive.org/web/20120202003013/http://www.ecglibrary.com/ecghist.html
  | url-status = live
  }}</ref>

=== Etymology ===
The word is derived from the [[Greek language|Greek]] ''electro'', meaning related to electrical activity; ''kardia'', meaning heart; and ''graph'', meaning "to write".<ref>{{Cite web |last= |first= |title=The Interesting History of EKGs |url=https://info.nhanow.com/blog/the-interesting-history-of-ekgs |access-date=2024-01-21 |website=info.nhanow.com |language=en-us}}</ref>