In the course of work with the electrocardiograph, there has come to my attention a phenomenon which introduces an error so large as to be of considerable importance. It is evident in Figure 1, and consists in the fact that when a constant difference of potential is applied at two points of the circuit containing the galvanometer and the patient, the resulting deflection of the string takes the form of a quick jump, as quick as the instrument can make, followed by a slow partial return toward the base line. The return takes the form of a curve such as can be seen in the figure (Fig. 1), and has a duration of from 0.1 to 0.4 second in different instances, being short when the overshoot is small, longer when it is large. When the string reaches this new level the deflection remains constant, the movements due to the heart's
PARDEE HEB. AN ERROR IN THE ELECTROCARDIOGRAM ARISING IN THE APPLICATION OF THE ELECTRODES. Arch Intern Med (Chic). 1917;XX(2):161–166. doi:10.1001/archinte.1917.00090020002001
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