Algorithms of ECG Time Series Processing in EDF-Format

The Python script for reading digital cardiac signal in EDF format and its spectral analysis was developed. The discrete Fourier series decomposition of one period of the cardiac signal was performed. The deviation of the Fourier image from the original cardiac signal was investigated. This deviation was found to be minimal if the number of harmonics is two times less than the number of cardiac signal readings within the duration of the R-R interval. The adequacy of the author’s software for spectral research was confirmed by synthesizing the signal from the Fourier image and comparing the original and synthetic signals. A practically functional dependence of the spectrum on the type of cardiac signal envelope was revealed. The sensitivity of the spectral analysis compared with visual identification of the cardiac waveform is evaluated. The applicability of the Fourier image of the cardiac signal for diagnosing temporary distortions of the heart rhythm, as well as the use of this image as a vector of the state of the heart, has been established. The prospects for developing this research are noted, for example, using methods of mathematical statistics and practical testing of the results with the participation of cardiologists. The theoretical significance of the proposed study consists in specifying the methodology of the Fourier transform application for the analysis of cardiac signals for diagnostic purposes using computer technologies. The results obtained in the course of the study are of practical value for the development of medical devices and software. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2026.