The effect of parameters of electrocardiograph measuring channel on recordings of micropotentials of the heart

The paper presents the research findings on the total effect of different types of filters on the electrocardiogram (ECG) signal recorded by a high-resolution electrocardiograph based on nanoelectrodes without filters in the band from 0 to 150 Hz. A standard block diagram of one ECG channel includes both amplifiers and a number of filters: a high-pass filter, a filter of constant component, a low-pass filter, an anti-aliasing filter, a rejection filter, and others. The method of computer simulation was used to study the effect of the fine structure distortions (low-amplitude high-frequency fluctuations) of the heart biopotentials caused by the filter circuits. The simulation was performed using the LabVIEW software package. It is shown that the filters distort the shape and amplitude of the heart micropotentials, and intro¬duce phase shifts or remove them from the output signal of the considered ECG. It is essential to consider signal filtering when applying the amplitude and time diagnostic criteria. In some cases, application of diagnostic criteria to the filtered signal can produce erroneous results.