Using gaussians to model increment distribution of the long-term R-wave interval in healthy humans

The fluctuation in the long-term R-wave interval recording can range from a few milliseconds to approximately 1 s in healthy humans. The large fluctua tion has been characterized by the 1/f-like power spectrum. This implies sc ale invariance symmetry of the signal, which is closely related to the fami ly of probability density function of the increment process. In this paper, the distribution of the increment of the R-wave interval was studied. The increment of the R-wave intervals typically evolves from a stretch-exponent ial-like distribution in the small time interval to a near gaussian distrib ution in the large time interval. The model proposed by Hausdorff and Peng, consisting of summing a set of gaussian components, can be used to explain the transition. However, it requires further modification in order to capt ure the experimental data properly. The new model suggests, among other thi ngs, multiple scaling in HRV. (C) 2001 Elsevier Science Ltd. All rights res erved.