Wavelet representation comparison for heart rate variability analysis

Wavelet time-frequency representation has become one of the most useful tools for research today. This paper presents a comparison of three different wavelets used for heart rate variability (HRV) studies. It is an attempt to reveal some underlying differences to readers about the wavelet representations. Topics introduced include the time-frequency plots obtained by using the Morlet, Daubechies 4 and Haar wavelets on the interpolated interbeat interval signal (IIBI) derived from the electrocardiogram (ECG) of a subject at rest breathing at 16 breaths per minute.