Skin-electrode impedance problems in electrocardiography
1968; Elsevier BV; Volume: 76; Issue: 4 Linguagem: Inglês
10.1016/0002-8703(68)90138-5
ISSN1097-6744
AutoresAlan S. Berson, Hubert V. Pipberger,
Tópico(s)Cardiac electrophysiology and arrhythmias
ResumoThe effects of skin to electrode impedance on ECG potentials were determined by recording Frank leads with and without buffer amplifiers on 24 patients over a 15-minute period. Recordings were taken every 5 minutes without moving the electrodes in order to study the effects as a function of time. Electrode to skin resistance was measured every 5 minutes at each electrode site. The results demonstrated that skin to electrode impedance values were extremely variable and unpredictable, ranging between 0 and 206 K at 10 Hz. In most instances, they decreased with time. Errors in Q, R, S, and T wave amplitudes, measured using a digital computer, occurred in 17 of the 24 patients as a result of skin to electrode impedances. These errors were effectively minimized when buffer amplifiers at each electrode were used. It is recommended that buffer amplifiers having at least 10 megohms input impedance at low frequencies be employed in ECG recording whenever weighting networks are used between the electrodes and the recording device. In the use of standard leads with present day direct-writers, it has been demonstrated that skin to electrode impedances may produce amplitude errors in the recorded potentials, especially in those leads which require the use of a central terminal. Buffer amplifiers, when used for the limb electrodes, will effectively prevent such errors in the recording of conventional precordial and augmented leads.
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