Dynamical non-linear analysis of heart rate variability in patients with aortic stenosis

In this study the 24-h Heart Variability Signals (HRV) of 206 patients with Aortic Stenosis (AS) and 68 healthy subjects (NRM) were analyzed, using dynamical nonlinear analysis to compare the complexity of the signals between these two groups during morning (7-12h), afternoon (15-20h) and night (0-5h). The dynamical analysis defines an initial window of 10,000 beats and calculates the Correlation Dimension (CD) as a non-linear index. Then the window is moved 2,500 beats on the time series and the CD of the new window is calculated. This process is repeated until the whole signal is analyzed. It was found that: 1) The CD of HRV has significant lower values in the morning than in the night for both groups. 2) The CD of males is lower than the CD values of females during morning for both groups. 3) The CD of NRM is lower than the CD of AS during the morning, while in the night the CD of NRM males is higher.