We applied multiresolution wavelet analysis to the sequence of times between
human heartbeats (R-R intervals) and have found a scale window, between 16 and
32 heartbeats, over which the widths of the R-R wavelet coefficients fall into
disjoint sets for normal and heart-failure patients. This has enabled us to
correctly classify every patient in a standard data set as either belonging to
the heart-failure or normal group with 100% accuracy, thereby providing a
clinically significant measure of the presence of heart-failure from the R-R
intervals alone.
Comparison is made with previous approaches, which have provided only
statistically significant measures.Comment: 5 pages, 4 figures, to appear in Phys. Rev. Letter