|HISTORY OF MEDICINE
|Year : 2019 | Volume
| Issue : 4 | Page : 181-183
The invention of electrocardiography machine
Amar M Salam
Department of Medicine, College of Medicine, Qatar University, Doha, Qatar; Weill Cornell Medical College, New York, USA; Department of Cardiology, Al-Khor Hospital, Hamad Medical Corporation, Doha, Qatar
|Date of Submission||17-Oct-2019|
|Date of Acceptance||17-Oct-2019|
|Date of Web Publication||14-Nov-2019|
Dr. Amar M Salam
Department of Cardiology, Al-Khor Hospital Hamad Medical Corporation, P.O. Box: 3050, Doha, Qatar
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Salam AM. The invention of electrocardiography machine. Heart Views 2019;20:181-3
The development of electrocardiography (ECG) machine 120 years ago revolutionized the study of heart disease. The ECG has become one of the most commonly used tests in patients' evaluation and an essential part of cardiac assessment in the modern era.
The initial attempts to record the human heart electrical activity were performed with a mercury capillary electrometer by Augustus Waller in May 1887 at St. Mary's Hospital, London. The capillary electrometer consisted of a glass tube containing mercury with one end drawn out into a fine capillary (20–30 μm) and immersed vertically in dilute sulfuric acid [Figure 1]. Measurement was based on the displacement of the mercury meniscus because mercury contracts and expands according to the potential difference between the mercury and acid which are connected to electrodes on two points on the body. The tracings were poor however and exhibited only two distorted deflections.
Willem Einthoven (Leiden, The Netherlands) is considered the founder and father of modern ECG. Einthoven began his studies of the ECG with the mercury capillary electrometer and improved its distortion mathematically, so that he was finally able to register a good representation of the ECG before the beginning of the twentieth century [Figure 2]. He later further improved ECG recordings with the introduction of a string galvanometer that he designed [Figure 3].
|Figure 2: Early recording by Einthoven using the modified capillary electrometer|
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Einthoven published a preliminary report of the string galvanometer in 1901 and a more detailed description in 1903, which included a report of ECGs taken with his string galvanometer [Figure 4]. “The string galvanometer is essentially composed of a thin silver-coated quartz filament (about 3 μm thick), which is attached like a string in a strong magnetic field. When an electric current is conducted through this quartz filament, the filament reveals a movement which can be observed and photographed by means of considerable magnification; this movement is similar to the movement of the capillary electrometer. It is possible to regulate the sensitivity of the galvanometer very accurately within broad limits by tightening or loosening the string.” The original apparatus was huge in size as it filled two rooms, weighed 600 pounds, included an enormous electromagnet, and required five people to operate it. Overheating required a huge continuous-flow water jacket for cooling the electromagnet. Large buckets of saline were used as electrodes with the subject immersing his hands and feet in them [Figure 5].
|Figure 4: The first electrocardiogram recorded using Willem Einthoven's string galvanometer (1901)|
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|Figure 5: Willem Einthoven testing the string galvanometer on a patient (1916)|
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Einthoven developed a system of electrocardiographic standardization that continues to be used all over the world and introduced the triaxial bipolar system with three limb leads and thus established uniformity of the recording process. Einthoven also conceived the famous equilateral triangle with leads I, II, and III at its sides and the calculation of the electrical axis (in the frontal plane) depicted as a single vector with an arrow at the center of the triangle.
Since the time of Einthoven, the use and application of the ECG has grown steadily and tremendously and ECG has become an integral part of cardiac evaluation and management. This could not have happened without the visionary and dedicated work of scientists like Willem Einthoven, the father of modern ECG [Figure 6].
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| References|| |
Barold SS. Willem Einthoven and the birth of clinical electrocardiography a hundred years ago. Card Electrophysiol Rev 2003;7:99-104.
Sykes AH. A D Waller and the electrocardiogram, 1887. Br Med J (Clin Res Ed) 1987;294:1396-8.
Burchell HB. A centennial note on Waller and the first human electrocardiogram. Am J Cardiol 1987;59:979-83.
Einthoven W. Un nouveau galvanom'etre. Arch N'eerl Sci Exactes Nat 1901;6:625-33.
EinthovenW. Die galvanometrische registerung des menschlichen elektrokardiogram: Zugleich eine beurtheilung der anwendung des capillar–elektrometers in der physiologie. Pflugers Arch ges Physiol 1903;99:472-80.
EinthovenW. The different forms of the human electrocardiogram and their signification (Chelsea lecture). Lancet 1912;1:853-61.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]