Fractal changes in heart rate dynamics with aging and heart failure

摘要

In this work we analyze interbeat cardiac time series arising of three groups: healthy young and healthy elderly subjects and patients with congestive heart failure. We use the fractal dimension method proposed by Higuchi. We find that fractal organization is different for each group. In the case of healthy young subjects only one value of the fractal dimension is necessary to fit the interbeat data, whereas in the cases of healthy elderly and patients with congestive heart failure a crossover behavior in the fractal dimension is present but in opposite directions. By means of a "zoom" on the hinges of the crossover point interesting effects of aging are presented. Finally, we discuss our results in the context of heart interbeat dynamics.