Multiresolution wavelet analysis of heart rate variability for heart-failure and heart-transplant patients

We have carried out a study on a collection of electrocardiograms from patients who suffer from congestive heart failure, heart-transplant patients, and normal subjects, using wavelet-based multiresolution techniques and receiver-operating-characteristic (ROC) analysis. The scale-dependent wavelet-coefficient standard deviation /spl sigma//sub wav/(m) is found to be superior to two commonly used heart-rate-variability measures for diagnosing cardiac dysfunction, the interbeat-interval standard deviation /spl sigma//sub int/ and the spectral scaling exponent /spl delta/. A recent Israeli-Danish study of diabetic patients that confirms our observations is discussed.