Diseases of the chest and the principles of physical diagnosis . 65 60 55 50 45 40 35 30 25 20 29 to 32 65 60 55 50 45 40 35 30 25 20 15 33 to 36 60 00 50 45 40 35 30 25 20 15 10 37 to 40 55 50 45 40 35 30 25 20 15 10 5 41 to 44 50 45 40 35 30 25 20 15 10 o 0 Note.—In case of increase in pressure higher than -HIO add 3 per cent, to the+ 10 column for each 2 mm. in excess of 10. CHAPTER XVI THE ELECTROCARDIOGRAPH By Edward B. Krumbhaar, Ph. D., M. D. Among the instruments of precision recently become available forclinical purposes is the electrocardiograph, adapted from Einthovensstring galvano
Diseases of the chest and the principles of physical diagnosis . 65 60 55 50 45 40 35 30 25 20 29 to 32 65 60 55 50 45 40 35 30 25 20 15 33 to 36 60 00 50 45 40 35 30 25 20 15 10 37 to 40 55 50 45 40 35 30 25 20 15 10 5 41 to 44 50 45 40 35 30 25 20 15 10 o 0 Note.—In case of increase in pressure higher than -HIO add 3 per cent, to the+ 10 column for each 2 mm. in excess of 10. CHAPTER XVI THE ELECTROCARDIOGRAPH By Edward B. Krumbhaar, Ph. D., M. D. Among the instruments of precision recently become available forclinical purposes is the electrocardiograph, adapted from Einthovensstring galvanometer. In the short space of time elapsed since its inven-tion in 1903, it has not only already proved its clinical value as the mostaccurate analyzer of cardiac arrhythmias, but bids fair to give furtherinformation about the cardiac muscle that is obtainable in no other the hands of Lewis, Rothberger and Winterberg, Einthoven and others,it has materially aided in increasing our knowledge of the mechanismof the heart beat, both in health and Fig. 144.—An electrocardiograph station. A, string galvanometer; B, registering ap-paratus (camera); C, electric light; D, rheostat; E, leads from which current is taken.(After Hoffman.) The Princple.—The string galvanometer depends on the principlethat a conducting string or wire lying in a strong magnetic field, if suffi-ciently sensitive, will move vertically to the lines of force when an electriccurrent passes through it. As every contracting muscle initiates such acurrent (the part at which the contraction starts becoming electricallynegative to the rest of the muscle), the contractions of the various cham-bers of the heart cause a series of such deflections. These minute currents ;184 THE ELECTROCARDIOGRAPH 185 radiating through the body, if the extremities of the patient are connectedwith the galvanometer by suitable non-polarizable electrodes, may be per-petuated as a graphic record by photographing the shadow
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectdiagnos, bookyear1920
