SCALE-INDEPENDENT MEASURES AND PATHOLOGICAL CARDIAC DYNAMICS

We study several scale-independent measures of cardiac interbeat inter val dynamics defined through the application of the wavelet transform. We test their performance in detecting heart disease using a database consisting; of records of interbeat intervals for a group of healthy individuals and subjects with congestive heart failure. We find that s cale-independent measures effectively distinguish healthy from patholo gic behavior and propose a new two-variable scale-independent measure that could be clinically useful. We compare the performance of a recen tly proposed scale-dependent measure and find that the results depend on the database analyzed and on the analyzing wavelet.