Direct-recording ambulatory electrocardiographic monitoring systems may produce serious errors not only because of their restricted bandwidth, but even more because of the "half-wavelength-to-head-contact effect." This article describes an easy measurement procedure and a mathematic model of the storage medium. The frequency response is calculated by way of five data from a single measurement. Some errors of typical recorders are discussed with the help of synthesized electrocardiographs. Measurements by six different recorders are listed.
Institute for High Frequency Techniques, Faculty of Electrical Engineering, University of the Bundeswehr Munich, Federal Republic of Germany.
Med Instrum. 1988 Feb 1; 22 (1): 2-11.
AbstractDirect-recording ambulatory electrocardiographic monitoring systems may produce serious errors not only because of their restricted bandwidth, but even more because of the "half-wavelength-to-head-contact effect." This article describes an easy measurement procedure and a mathematic model of the storage medium. The frequency response is calculated by way of five data from a single measurement. Some errors of typical recorders are discussed with the help of synthesized electrocardiographs. Measurements by six different recorders are listed.