Friday, October 11, 2019

History of Electrocardiography Machine Essay

History of electrocardiography prevails over two centuries as an intellectual exercise as the process of inventing an electrocardiogram started with the Galvani’s idea of animal electricity. In 1842 this idea was further reinforced by Italian physicist Carlo Matteucci who illustrated by his experiments that electric current could be quantified from inactive heart muscle. German physiologist Emil Dubois-Reymond further explored this phenomenon and confirmed Carlo Matteucci’s conclusion and labeled this changing current in the resting muscle as â€Å"action potential†. He further developed a device that could deliver stimulation pulses to the muscles and was capable of computing discharge current of muscles at short intervals. In 1856 Rudolph von Koelliker and Heinrich Muller recorded an â€Å"action potentialâ€Å"on the spotaneous beating heart. But the major development came in 1872 when French physicist Gabriel Lippmann introduced a capillary electrometer. This capillary electrometer was based on the principle of â€Å"polarization† and â€Å"surface tension†. Structurally it was a slender glass tube with mercury-sulphuric acid base. The mercury meniscus stirred with the influx of electrical potential and was observable by a microscope. In 1893, Willem Einthoven who is considered as the inventor of modern electric cardiogram and its various principles used the term ‘electrocardiogram’ at a conference of the Dutch Medical Association. But major development occurred during the three years staring from 1901 when Einthoven dissatisfied with capillary electrometer and it slow response, designed a string galvanometer. This galvanometer contained a string eletromagnet to produce a magnetic flux, two piece poles, a quartz string between the two piece poles, peepholes in the two piece poles to observe the position of string. It further contained a lamp and timing systen to examine the shadow of string at different time intervals. The weight of this whole apparatus was about 600 pounds. He further modified the string galvanometer to invent a more effective electrocardiograms. However in 1902, Einthoven brought out the first electrocardiogram that was recorded on his string galvanometer. This was a giant’s leap in the history of bio-medical. In order to produce string galvanometer on commercial level, Einthoven discussed the possibilities with Horace Darwin of Cambridge Scientific Instruments Company of London. So this event made the electrocardiogram to come out of experimentation and to be used in medical profession. Einthoven, in 1906, circulated the first presentation electrocardiograms recorded with a string galvanometer. These electrocardiograms included the specimen of left and right ventricular and atrial, atrial flutter, ventricular premature beats etc. In 1910, Horatio Williams who was professor at Cornell University Medical College, New York issued electrocardiograms of patient that manifest atrial and ventricular ectopics, ventricular hypertrophy, atrial fibrillation and ventricular fibrillation that were recorded in hospital using a complex system of cables. This was first large-scale use of electrocardiograms in the hospitals. With the advent and introduction of vacuum tubes, the electric galvanometer was further modified and improved. In 1926, Ernestine and Levine used these vacuum tubes to produce enlarged images. Cathode rays tube further helped to produce portable electrocardiograms. Today electrocardiograms works on the same principles that were devised Einthoven in the first decade of 20th century. References Burchell HB. A centennial note on Waller and the first human electrocardiogram. Am J Cardiol 1987; 59:979-983 Burch, G.E. A History of Electrocardiography. Chicago. Year Book Medical. 1964. Burnett J. The origins of the electrocardiograph as a clinical instrument. Medical History Supplement 5: 1985, 53-76. Published as a monograph. The emergence of modern cardiology. Bynum WF, Lawrence C, Nutton V, eds. Wellcome Institute for the History of Medicine:1985. Fye WB. A history of the origin, evolution, and impact of electrocardiography. Am J Cardiol 1994;73:937-949 Plonsey, R. Bioelectric Phenomenon. New York. McGraw-Hill. 1972.

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