Scaling Exponent Determined by a Bio-Signal Computation for the Healthy
and Diseased Heartbeat
Toru Yazawa, Katsunori Tanaka, Atsushi Kato, Tomoo Katsuyama
We analyzed heartbeat-intervals by using our own program of
detrended fluctuation analysis (DFA). “Alternans” is an
arrhythmia exhibiting alternating amplitude or alternating
interval from heartbeat to heartbeat, which was first described in
1872 by Traube. Recently, alternans was finally recognized as
the harbinger of a cardiac disease because physicians noticed
that an ischemic heart exhibits alternans. To quantify irregularity
of the heartbeat including alternans, we used the DFA and
revealed that the alternans rhythm lowers the scaling exponent.
We conclude that the scaling exponent calculated by the DFA
reflects a risk for the “failing” heart. The scaling exponents
could determine whether the subjects are under sick or healthy
conditions on the basis of cardiac physiology.