Studying the clinical significance of ultra-low frequency band power spectra from heart period signal by comparative banded running spectra

The banded running spectra of heart period signal (HPS) before and after physical or pharmaceutical test were compared by comparative banded running spectra (CBRS) technique to study the clinical significance of HPS ultra-low frequency band (ULF:0.003-0.040 Hz). CM5 lead electrocardiosignal (ECS) from body surface was acquired at 300 Hz sampling rate, in 10 minutes, in order to get more than 512 heart periods (HP). R-R intervals from ECS were extracted to form digital time series, which were called HPS(n), using double searching method by searching maximal derivative and maximum. 16 HP were moved and 256 windowed (Blackman window) FFT for HPS(n) were completed each time. Banding the power spectra into three bands (ultra-low frequency band, ULF:0.003-0.04 Hz; low frequency band, LF:0.04-0.14 Hz; high frequency band, HF:0.14-0.5 Hz) formed the three banded self-normalized (or self-adapted) running spectra. CBRS before and after physical or pharmaceutical tests were formed on the same scale. From graphic and data results, it can be concluded that the ULF band of HPS spectra reflect the sympathetic activity. The LF band is a mixed band or transition band which generally represents both the sympathetic and the parasympathetic activity: sometimes the sympathetic is stronger, sometimes it is weaker, sometimes it is none. The HF band reflects the parasympathetic activity.