Effect of respiration harmonics on beat-to-beat analysis of heart signal

Doppler radar is a potential tool for non-invasive physiological monitoring. However, its signal is affected by respiration harmonics interference which is an inherent respiratory feature. Moreover, the usability of Doppler radar is decreased for sophisticated beat-to-beat analysis of heart signals in presence of such interference. This paper aims to identify the causes of these harmonics along with proposing the utilization of Maximal overlap discrete wavelet transform (MODWT) for minimizing their interference. The results are presented in terms of average heart rate and the standard deviation of interbeat intervals (SDNN). Adaptive IIR notch filter is used for comparing the effect of harmonics cancellation on beat-to-beat analysis of heart signal. Compared to the results of the notch filter, the SDNN difference from MODWT is lowered by 5.12% to 91.43%.