Time-varying analysis for the estimation of spectral parameters in cardiovascular variability signals

The frequency domain analysis of the heart rate variability (HRV) signal is actually extended to nonstationary situations in order to quantify the autonomic control during physiological or pathological dynamical phenomena. Different methods of time-frequency representation of a signal have been proposed in literature. In the present paper a recursive implementation of the autoregressive spectral identification is described together with application in clinical protocols dealing with myocardial ischemia, both spontaneous or induced by dipyridamol infusion and with episodes of vaso-vagal syncope.