Electrocardiogram's distortions due to a high skin-electrode resistance; a simple clinical method for measuring this resistance.

Abstract A high skin-electrode resistance affects the electrocardiogram in two ways: (1) producing an unbalanced central terminal through dissimilar contact in each of the three limb leads, and (2) giving distorted waves in any lead through skin and electrode capacitance. This last error is proportional to the ratio of the skin-electrode resistance to the total circuit resistance. Hence it is more common when using string electrocardiographs, but it is also found in those amplifier instruments which have low input impedance. Usually, the distorted waves are more noticeable in precordial Leads V 1 and V 2 and may be recognized in many tracings reproduced in papers and textbooks concerning cardiology. For these reasons, a clinical method for measuring the actual skin resistance seems highly desirable. Such a method, applicable to any type of electronic apparatus and requiring a 5,000 or 10,000 ohm resistor as the only additional component, is described. Formulas are given which allow the determination of skin resistance under any limb or precordial electrode.