| It is well-known that
healthy heartbeats are chaotic rather than regular. |
| A careful plot of heart rates over
several time scales reveals self-similar scaling.
See Goldberger, Rigney and West. |
| To illustrate this phenomenon, here is a plot of the intervals
between successive heartbeats from a fetal heart. The intervals range from 0.341 sec
to 0.447 sec. The record contains 2719 intervals. |
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| Next is a plot of one-fifth this data, taken from near the end of
the plot, and presented in the same aspect ratio as the whole plot. |
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| Certainly the whole plot appears denser, but then it contains five times
as many points as the second. |
| For a better comparison, the next picture is a
plot of every fifth point of the original data. |
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