Time-frequency analysis of the heart rate variability during the Valsalva manoeuvre

We present an analysis of the heart rate variability during the Valsalva ma noeuvre. The more frequently used time-frequency distributions were applied in order to analyse the dynamical behaviour of several spectral indexes du ring the manoeuvre. The influence of the branches of the autonomous system can be predicted following the evolution of the studied indexes. The expone ntial time-frequency distribution showed the best results in the graphical representation, as well as in the indexes calculation. The total power, the low-to-high frequency ratio and the fractal dimension were analysed throug hout the different phases of the manoeuvre and a representative model of th ese parameters evolution was proposed.