Phys Rev Lett. 1993 Mar 1;70(9):1343-6.  

Long-range anticorrelations and non-Gaussian behavior of the heartbeat.

Peng C-K, Mietus J, Hausdorff JM, Havlin S, Stanley HE, Goldberger AL.

Center for Polymer Studies and Department of Physics, Boston University,
Massachusetts 02215.

We find that the successive increments in the cardiac beat-to-beat intervals of
healthy subjects display scale-invariant, long-range anticorrelations (up to
10(4) heart beats).  Furthermore, we find that the histogram for the heartbeat
intervals increments is well described by a Levy stable distribution.  For a
group of subjects with severe heart disease, we find that the distribution is
unchanged, but the long-range correlations vanish.  Therefore, the different
scaling behavior in health and disease must relate to the underlying dynamics of
the heartbeat.

PMID: 10054352 [PubMed - indexed for MEDLINE]