Chapter 1: The Creation of Electrocardiography

J. Willis Hurst, MD

 [Ventricular Electrocardiography © 1991, 1998 J. Willis Hurst, MD]

 Bancraft and the Torpedo Fish

 Louis N. Katz and Herman K. Hellerstein wrote a scholarly discussion on the evolution of our knowledge of electrocardiography and published it in Circulation of the Blood: Men and Ideas edited by Fishman and Richards.[1]* Interested readers will be spellbound to discover how early observers gradually began to understand that lightning, lodestone, amber (when rubbed), and the torpedo fish had something in common -- electricity!

 Apparently, the torpedo fish was the subject of great interest. Bancraft, in 1676, suggested that the strange fish was capable of delivering a shock of electricity.[2] John Walsh,[3] John Hunter,[4] and Henry Cavendish[5]supported Bancraft's contention. Accordingly, it was gradually accepted that certain animals generated electrical current.

 Luigi Galvani (1737-1798) can be acclaimed as the scientist who proved that electrical stimulation of the crural nerves of a frog would make the frog's leg muscles contract. In his own account[6,7] of this important experiment, he wrote:
 
 

The course of the work has progressed in the following way. I dissected a frog and prepared it. Having in mind other things, I placed the frog on the same table as an electrical machine...so that the animal was completely separated from and removed at a considerable distance from the machine's conductor. When one of my assistants by chance lightly applied the point of a scalpel to the inner crural nerves...suddenly all the muscles of the limbs were seen so to contract that they appeared to have fallen into violent tonic convulsions. Another assistant who was present when we were performing electrical experiments thought he observed that this phenomenon occurred when a spark was discharged from the conductor of the electrical machine. Marvelling at this, he immediately brought the unusual phenomenon to my attention when I was completely engrossed and contemplating other things. Hereupon I became extremely enthusiastic and eager to repeat the experiment so as to clarify the obscure phenomenon and make it known. I myself, therefore, applied the point of the scalpel first to one then to the other crural nerve, while at the same time some one of the assistants produced a spark; the phenomenon repeated itself in precisely the same manner as before. Violent contractions were induced in the individual muscles of the limbs and the prepared animal reacted just as though it were seized with tetanus at the very moment when the sparks were discharged.
Galvani and Volta had their differences but each stimulated the other to extensive experimentation.[8] Galvani discovered in an experiment in which no metal was used, that when the nerve of one frog was placed on the injured muscle of another frog, the muscles of the first frog would contract.[6]

 As time passed, many workers pursued the mysteries of animal electricity, including the great Emil DuBois-Reymond.[9] The next giant step was taken by Kolliker and Muller,[10] who placed the nerve portion of a nerve-leg preparation of one frog on the beating heart of another frog. The frog's leg contracted each time the heart contracted.
 
 

Back The First Measuring Device

These investigators soon recognized that a measuring device was needed. Dr. DuBois-Reymond invented the rheotome which interrupted the current in such a fashion that the heart's own current could be recorded with a galvanometer.[11] Marchand in 1877[12] and Engelmann in 1878[13] were among the first to record the electrocardiogram from the surface of the heart of a lower animal.

 The search for improved measuring devices continued until the mercury capillary electrometer was invented by Gabriel Lippmann in 1875.[14] Augustus Waller (Fig. 1.1), who was destined to play a major role in the events that followed, wrote the following passage[15] about the device:

The instrument is, in fact, an exceedingly delicate electrical manometer; a rise of electrical pressure on the mercury side or a fall of electrical pressure on the sulphuric acid side, causes the mercury to move towards the point of the capillary; a fall of electrical pressure on the mercury side or a rise on the sulphuric acid side, causes the mercury to recede from the point of the capillary. The instrument accordingly is an indicator of "potential" or "pressure"; not of "current." Its delicacy is such that it will react to as little as 1/40,000 volt. It offers, moreover, the following advantages: the indications are practically instantaneous, free of lost time, and of after-oscillation; the resistance in the circuit is immaterial; unpolarisable electrodes may for most purposes be dispensed with.
Click to zoom Figure 1.1

 Augustus D. Waller (1856-1922). Using a mercury capillary electrometer, he was the first to record a human electrocardiogram.[15,17] (Photograph provided by and reproduced with permission of The National Library of Medicine, Bethesda, Md.)

Although Marey recorded the first electrocardiogram using the mercury capillary electrometer in 1876,[16] Waller was the first to record the electrocardiogram of a human heart. [17] Waller, who was born in Paris, later moved to London where he became Director of the Physiological Laboratory at the University of London. Sir Thomas Lewis (Fig. 1.2) wrote the following statement[17] about his contribution:
 
 

Waller was the first to show that currents set up in the beating of the human heart can be recorded; he was the first to obtain a human electrocardiogram.
Click to zoom Figure 1.2

Sir Thomas Lewis (1881-1945). Lewis extended the work of Einthoven. His pioneering work, for the most part related to understanding cardiac arrhythmias, influenced clinical practice throughout the world. (Photograph provided by and reproduced with permission of The National Library of Medicine, Bethesda, Md.)

The search for an improved measuring device continued. Willem Einthoven of Leiden, The Netherlands, who had heard Waller lecture in May of 1887 and witnessed the recording of an electrocardiogram, improved upon Ader's galvanometer [18] so that it could record the electrical current of the intact human heart. In Einthoven's words:[19]
 
 

The string galvanometer is essentially composed of a thin silver-coated quartz filament (about 3 microns thick): which is stretched 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 movements of the mercury contained in the capillary-electrometer. It is possible to regulate the sensitivity of the galvanometer very accurately within broad limits by tightening or loosening the string.
Einthoven (Fig. 1.3A) and his string galvanometer (Fig. 1.3B) soon gained international recognition. Einthoven labeled the waves of the electrocardiogram as P, Q, R, S, and T. Legend holds that he chose the letters from the center of the alphabet because he did not know what the waves meant, or whether other waves preceding the P wave and following the T wave would be discovered as the instrumentation improved (Fig. 1.3C). In fact, the U wave was added later.
f
 
Click to zoom

1.3A
Click to zoom

1.3B
Click to zoom

1.3C
Figures 1.3 A-C.

 A.Willem Einthoven (1860-1927). This Dutch physiologist improved Ader's galvanometer so that it would record the electrical current of the human heart.[18,19] Einthoven's instrument introduced the field of electrocardiography. (Photograph provided by and reproduced with permission of The National Library of Medicine, Bethesda, Md.)

 B. Einthoven's string galvanometer, Leyden model. (From Katz LN, Hellerstein HK: Electrocardiography. In Fishman AP, Richards DW (eds): Circulation of the Blood: Men and Ideas. New York, Oxford University Press, 1964, p 294, 295. (Reproduced with permission of Dr. A.P. Fishman.))

 C. Evolution of the electrocardiogram from the electrometer. The upper record was made using the capillary electrometer, the middle record is a "corrected curve," and the lower record was made using Einthoven's string galvanometer. (The upper and middle portions of this figure are from Einthoven W: Die galvanometrische Registrirung des menschlichen Elektrokardiogramms, zugleich eine Beurtheilung der Anwendung des Capillar-Elektrometers in der Physiologie. Archiv fur die Gesammte Physiologie des Menschen und der Thiere, 99:473, 1903. The exact source for the lower portion of this figure is unknown because it was not shown in the original figure published in 1903. It did appear in Fishman AP, Richards DW (eds): Circulation of the Blood: Men and Ideas. New York, Oxford University Press, 1964, p 295. (Reproduced with permission of Dr. A.P. Fishman.))

Sir Thomas Lewis of London (Fig. 1.2) extended the work of Einthoven. His pioneering work formed the basis for much of our current knowledge and influenced many clinicians throughout the world.[20]

 The brilliant work of Frank Wilson (Fig. 1.4) and his associates dominated the field for many decades. He developed a new lead system that permitted accurate recordings from new body positions, including the precordial sites (see Chapter 4). He emphasized the ventricular electrocardiogram and developed many new concepts,[21-33] which will be taken up in later discussions.
 
 
Click to zoom Figure 1.4

Frank Norman Wilson (1890-1952). Wilson and his associates dominated the field of electrocardiography for many decades. His research effort was directed toward understanding the ventricular electrocardiogram as well as arrhythmias. (Photograph provided by and reproduced with permission of The National Library of Medicine, Bethesda, Md.)

Back Modern Technology

As modern technology developed in the 1940s, the bulky machine designed by Einthoven was replaced by a more modern, portable, photographic electrocardiograph machine. Finally, the direct-writing machine was invented, and although it did not record with the precision of the photographic machine, its practicality soon made it the most frequently used instrument. Oscilloscopic recordings, or vectorcardiograms, were used during the 1950s and for a decade or so afterward. They were the most accurate of all recordings but they never gained widespread acceptance by clinicians, and as a practical tool, vectorcardiography did not survive. The machine and lead system used today are discussed in Chapter 4. Computer interpretation of electrocardiograms is now commonplace. The software varies with the manufacturer and, regrettably, none of the programs is accurate.

 Robert P. Grant (Fig. 1.5) was a creative genius. While working at Emory University in Atlanta, he built on the work of Einthoven, Lewis, and Wilson, and developed a way to apply vector concepts to the interpretation of a 12-lead electrocardiogram. The results of his investigations were published, with the collaboration of Harvey Estes, in Spatial Vector Electrocardiography.[34] This book, as well as the Atlas of Spatial Vector Electrocardiography by J. Willis Hurst and Grattan Woodson, could not have been written without the basic contribution of Robert Grant.[35]
 
 
Click to zoom Figure 1.5

Robert Purves Grant (1915-1966). While working at Emory University, Grant developed the concept of vector electrocardiography, which enabled the observer to characterize the electrical forces responsible for the electrocardiogram. His concepts, based mainly on the work of Wilson, form the basis for this book. (Photograph provided by and reproduced with permission of The National Library of Medicine, Bethesda, Md.)

 
* I thank Dr. Hellerstein, Dr. Fishman, and the Oxford University Press for permitting me to abstract certain parts of the chapter on electrocardiography in Circulation of the Blood: Men and Ideas.[1]

References

  1. Katz LN, Hellerstein HK: Electrocardiography, in Fishman AP, Richards DW (eds): Circulation of the Blood: Men and Ideas. New York: Oxford University Press; 1964:265.
  2. Fleming JA: Electricity, in Encyclopedia Britannica Cambridge, England: Cambridge University Press; ed 11, Vol 9, 1910:179.
  3. Walsh J: Of torpedoes found on the coast of England. Philos Trans R Soc Lond (Biol) 1773-75,64:464.
  4. Hunter J: Anatomical observations on the torpedo. Philos Trans R Soc Lond(Biol) 1773,63:481.
  5. Cavendish H: An account of some attempts to imitate the effects of the torpedo by electricity. Philos Trans R Soc Lond (Biol) 1776;66: 196.
  6. Galvani L: De viribus electricitatis in motu musculari commentarius. De Bononiensi Scientarium et Artium Instituto atque academia Commentarii 1791;7:363-418.
  7. Cohen IB: Introduction, in Galvani L: Commentary on the Effects of Electricity on Muscular Motion, M G Foley (trans). Norwalk, CT, Brundy Library, 1954.
  8. Galvani L: Dell'uso e dell'Attivita dell'Arco Conduttore nelle Contrazioni di Muscoli. Bologna, Tommaso d'Aquino, 1794.
  9. DuBois-Reymond E: Untersuchungen über Thierische Elektricitat. Berlin, Reimer, 1848-60, Vols 1 and 2.
  10. Kolliker A, Muller H: Zweiter Bericht über die im Jahr 1854/55 in der physiologischen Anstalt der Universität Wurzburg angestellten Versuche. Vll. Nachweis der negativen Schwankung des Muskelstroms am naturlich sich contrahirender Muskel. Verh Phys-Med Ges Wurzb 1856; 6:528.
  11. Hoff HE, Geddes LA: The rheotome and its pre-history: A study in the historical interrelation of electrophysiology and electromechanics. Bull Hist Med 1957;31:327.
  12. Marchman R: Beitrage zur Kenntniss der Reizwelle und Contractionswelle des Herzmuskels. Pflügers Arch 1877; 15:511.
  13. Engelmann TW: Uber das Verhalten des thatigen Herzens. Pflügers Arch 1878,17:68.
  14. Lippmann G: Relations entre les phenomènes électriques et capillaires. Ann Chir (Phys.) (Ser. 5) 1875,5:494.
  15. Waller AD: An Introduction to Human Physiology, ed 2. New York: Longmans Green;1893.
  16. Marey EJ: Des variations électriques des muscles et du coeur en particulier, étudiées au moyen de l'électromètre de M. Lippmann. C R Acad Sci (Paris) 1876;82:975.
  17. Lewis T: Comments in obituary notice of A. D. Waller. Br Med J 1922,1:458.
  18. Ader C: Sur un nouvel appareil enregistreur pour cables sousmarins. C R Acad Sci(Paris) 1897,124:1440.
  19. Einthoven W: The galvanometric registration of the human electrocardiogram, likewise a review of the use of the capillary-electrometer in physiology. In Willius FA, Keys E (eds): Cardiac Classics, Willius FW (trans). St Louis: CV Mosby; 1941.
  20. Lewis T, Rothschild MA: The excitatory process in the dog's heart. Part II. The ventricles. Philos Trans R Soc Lond (Biol) 1915;206:181.
  21. Wilson FN: A case in which the vagus influenced the form of the ventricular complex of the electrocardiogram. Arch Intern Med 1915; 16: 1008.
  22. Wilson FN: The distribution of the potential differences produced by the heart beat within the body and at its surface. Am Heart J 1930;5:599.
  23. Wilson FN, Bryant JM, Johnston FD: On the possibility of constructing an Einthoven triangle for a given subject. Am Heart J 1949;37:493.
  24. Wilson FN, Johnston FD: The vectorcardiogram. Am Heart J 1938; 16:14.
  25. Wilson FN, Johnston FD, Barker PS: The use of the cathode ray oscillograph in the study of the monocardiogram. J Clin Invest 1937; 16:664.
  26. Wilson FN, Herrmann GR: Bundle branch block and arborization block. Arch Intern Med 1920;26:153.
  27. Wilson FN, Johnston FD, Hill IGW: The interpretation of the galvanometric curves obtained when one electrode is distant from the heart and the other near or in contact with the ventricular surface. Part 11. Observations on the mammalian heart. Am Heart J 1934; 10: 176.
  28. Wilson FN, Johnston FD, Rosenbaum FF, et al: On Einthoven's triangle, the theory of unipolar electrocardiographic leads, and the interpretation of the precordial electrocardiogram. Am Heart J 1946;32:277.
  29. Wilson FN, Macleod AG, Barker PS: The interpretation of the initial deflection of the ventricular complex of the electrocardiogram. Am Heart J 1931;6:637.
  30. Wilson FN, Macleod AG, Barker PS: The potential variations produced by the heart at the apices of Einthoven's triangle. Am Heart J 1931;7:207.
  31. Wilson FN, Macleod AG, Barker PS: The Distribution of the Currents of Action and of Injury Displayed by Heart Muscle and Other Excitable Tissues. Ann Arbor, University of Michigan Press, 1933.
  32. Wilson FN, Macleod AG, Barker PS, et al: The determination and the significance of the areas of the ventricular deflections of the electrocardiogram. Am Heart J 1934; 10:45.
  33. Wilson FN, Macleod AG, Barker PS, et al: The electrocardiogram in myocardial infarction with particular reference to the initial deflections of the ventricular complex. in Johnston FD, Lepeschkin E (eds): Selected Papers, F N Wilson. Ann Arbor, Ml, Edwards, 1954.
  34. Grant RP, Estes EH: Spatial Vector Electrocardiography. Philadelphia, New York, Toronto: The Blakiston Company; 1951.
  35. Hurst JW, Woodson GC: Atlas of Spatial Vector Electrocardiography. New York, Toronto: The Blakiston Company; 1952.

Copyright information: Ventricular Electrocardiography by J. Willis Hurst, MD, was initially published by Gower Medical Publishing in 1991. The rights to the book were then transferred to Mosby Wolfe and in 1996 were returned to the author, Dr. Hurst.

 J. Willis Hurst, MD, received his degree from the Medical College of Georgia and served his residency in internal medicine at the same institution. He completed his cardiology fellowship with Dr. Paul White at Massachusetts General Hospital in Boston. Dr. Hurst was Professor and Chairman of the Department of Medicine of Emory University School of Medicine from 1957 to 1986. He received the Gifted Teacher Award and Master Teacher Award of the American College of Cardiology and the Distinguished Teacher Award from the American College of Physicians, and was designated a Master of the American College of Physicians. He served as President of the American Heart Association in 1972 and was given the AHA's Gold Heart and Herrick Awards. Dr. Hurst was Chairman of the Cardiovascular Board of the American College of Physicians for several years and served on the council of the National Heart, Lung, and Blood Institute. He was President Lyndon Johnson's cardiologist for 18 years. He is well known for the book The Heart and many other contributions to the medical literature. Currently, Dr. Hurst is Consultant to the Division of Cardiology of Emory University, and spends his mornings teaching and his afternoons writing.