Spectral components of heart rate variability determined by wavelet analysis

Spectral components of heart rate variability (HRV) are determined in the t ime-frequency domain using a wavelet transform. Based on the finer estimati on of low-frequency content enabled by the logarithmic resolution of the wa velet transform, corrections of spectral intervals, already defined by Four ier and model based methods, are proposed. The characteristic peaks between 0.0095 and 0.6, Hz. are traced in time and four spectral intervals are def ined, I(0.0095-0.021 Hz), II (0.021-0.052 Hz), III (0.052-0.145 Hz) and IV (0.145-0.6 Hz), within which peaks are located for all subjects included. T hese intervals are shown to be invariant regardless of the age and the stat e of the system. We also show that the frequency and power of the spectral components are related to age, AMI and particularly to type II diabetes mel litus.