RT Journal
T1 DIagnostic importance of electric variations in the heart
JF Journal of the American Medical Association
JO Journal of the American Medical Association
YR 1909
FD January 23
VO LII
IS 4
SP 300
OP 301
DO 10.1001/jama.1909.02540300040005
UL http://dx.doi.org/10.1001/jama.1909.02540300040005
AB The graphic studies on the venous and carotid pulse, the apex beat and the pulsations within the esophagus which have been applied clinically by Friedreich, Marey, François-Franck, Riegel, and in later years by James Mackenzie, Wenckebach, William His, Jr., G. A. and A. G. Gibson, D. Gerhardt, H. E. Hering, Hay and Rihl in Europe, and in America by Morrow, Erlanger, Hirschfelder, Schmoll, Hewlett, Cushny and Grosch, Cooper, Norris, Robinson, Thayer, Piersol and Bachman, have done much to enhance our knowledge of the disturbance of function in cardiac disease.A still further advance has been made by W. Einthoven of Leyden1 in placing the methods of electrophysiology at the disposal of the clinician. Einthoven has devised a galvanometer much more delicate than the capillary electrometer or any other form heretofore available. The movement of the fine quartz or platinum filament which occurs with changes of electric potential is magnified