Time-frequency analysis of the heart-rate variability during physical and physical-pharmacological tests

This paper presents the time-frequency analysis of the heart-rate variability (HRV) during the tilt test, the Valsalva maneuver, and controlled breathing. The tests were carried out both with and without dicyclomine hydrochloride which is an anticholinergic drug. In this paper, the authors employ the short-time Fourier transform (STFT), the Wigner-Ville distribution (WD), and Choi-Williams distribution (CWD) to characterize the HRV. They also compare the performance of these methods in applications to HRV.