Costa, Goldberger, and Peng Reply:

A Reply to the Comment by Vadim V. Nikulin and Tom Brismar.

Figure 1

Top: MSE analysis of the cardiac interbeat interval time series from healthy subjects and subjects with congestive heart failure (CHF). Error bars indicate standard error. Adapted from Ref. 2. Bottom: Ratio between the mean values of standard deviations for the coarse-grained time series (${\mathrm{S}\mathrm{D}}_n$) and the mean values of standard deviations for the original time series (${\mathrm{S}\mathrm{D}}_1$), plotted against scale factor.