Some Requirements in Equipment and Technics for Vectorcardiography

Abstract

To reduce the effects of extraneous potentials caused by muscle tremor, sweating, and interference from power circuits, it is desirable to restrict the frequency range of the cathode ray vectorcardiograph. Mathematical analysis of idealized waves and experiments with a photoelectric electrocardiographic generator indicate that a frequency range between the half-power frequency of 0.8 to 80 cycles per second is satisfactory for proper reproduction of most vectorcardiograms. Many investigators construct the vectorcardiogram graphically from the electrocardiogram. In this study it is shown that, unless simultaneous electrocardiograms recorded at greater than usual paper speed are used, such vectorcardiograms may be incorrect.