Spectral-time Mapping of Cardiorhythmograms in Micro-Cap

Method for analyzing transient regulation processes of the cardiovascular system was proposed. It is based on spectral-time mapping of cardiorhythmograms in the Micro-Cap structural and circuit modeling program. It is implemented with the help of a specially designed structural scheme based on the window fast Fourier transform. The result is presented in the form of pseudo three-dimensional images and two-dimensional maps, colored depending on the power of certain frequency components. Testing of the method was carried out using standard sinusoidal signals, cardiorhythmograms recorded in the subjects' calm state and during postural loads (static and dynamic). The method enables dynamic estimation of changes in power of frequency components of heart rhythm variability (HRV) in standard ranges: high frequency (HF), low frequency (LF) and very low frequency (VLF), and consequently changes in activity of sympathetic and parasympathetic systems.