Morphology evaluation of heart heart variability power spectrum

A relatively simple feature `fractal number´ reflects adequately differences in the morphology of power spectral patterns. The spectral region area ratios are well-known estimators of the heart rate variability but the fractal numbers are able to complementary evaluations of the particular spectral morphologies. The authors investigated 30 heart rate variability spectra and applied wave recognition techniques to the power density series of the R-R, Q-Q and S-S variability curves. Comparisons between spectral region area ratios and fractal number ratios showed the functionality of the morphology estimator as an appropriate complementary tool for clinical assessments of the sympatho-vagal balance at the sinus node