MSE_μ and MSE_MAD analysis of RR interval time series from healthy young and older individuals and patients with CHF using a fixed r value

We show the MSE analysis (Fig. 3) of RR interval time series using i) the mean and ii) the mean absolute deviation ( $\mathit{MAD} = \sum \vert x_i-\bar{x}\vert / N$) metrics for coarse-graining the time series. The parameter r is fixed at 8 ms. (The mean absolute difference is another measure of local variability.) The results indicate that healthy young subjects have the highest dynamical complexity, when considering both fluctuations in the mean and the mean absolute deviation (dispersion). The degrees of separation among the groups obtained with MSE_μ and MSE_MAD are qualitatively comparable. (The area under the curve (AUC) of younger versus older is 0.85 and 0.88 for MSE_μ and MSE_MAD, respectively. The AUC of healthy older individual versus patients with CHF is 0.85 and 0.90 for MSE_μ and MSE_MAD, respectively.

Figure 3: MSE analysis of mean (left) and absolute mean deviation (right) RR interval time series from healthy young and older subjects and patients with congestive heart failure, using a fixed r (8 ms) value. The sample entropy parameter m was 2. Time series length was 50,000 data points.