Description

The patterns of change over time (variability) contain valuable information about the state of overall system, representing an important means for clinical diagnosis and basic investigation. Physiological system serves as fascinating playground for the analysis techniques, which stems from the discipline of non-linear dynamics. Heart rate variability (HRV) refers to the beat-to-beat alterations in heart rate. HRV analysis is based on the concept that, fast fluctuations reflect the changes of sympathetic and vagal activity which results in variability of intervals between R waves i. e. „RR intervals“. In the current work HRV was assessed by traditional linear time and frequency-domain indexes, in parallel with the nonlinear Approximate Entropy, Threshold Acceleration change Index and Poincare plot analysis.