Phase-rectified signal averaging method applied to heart rate variability signals for assessment of the changes in sympathovagal balance during rest and tilt

The phase rectified signal averaging (PRSA) method is a technique initially developed to evaluate the acceleration and deceleration of the cardiac rhythm when applied to long-term-recordings of heartbeat intervals [1]. Because PRSA enables better cancellation of non-periodic or/and intermittent components, artifacts and impulsive noise, the quasi-periodic components are enhanced compared with classical Fourier analysis. Thus provides a higher accuracy for the detection of the most important frequencies. We propose to quantify the changes in sympathovagal balance by characterizing the PRSA power spectrum of heart rate variability (HRV) signals during rest and tilt. Synthetic and clinical HRV signals of short-term recordings are considered. The results demonstrate the PRSA capacity to significantly discriminate rest and tilt in terms of dominant frequencies. The bias and standard deviation of the estimated sympathovagal balance are also computed and compared with those obtained with a classical spectral method.