Measurement of continuous blood flow by thermodilution catheter takes into account measures that are intermittent, though the estimation of mean pressures is satisfactory. Natural pulsatile pulmonary circulation would remain unknown. To evaluate pulsatile pulmonary hemodynamics and its importance in right ventricular function, the calculation of impedance based on spectral analysis of pressure and flow waves would allow their respective contributions to resistance, elastance and wave reflection upon after right ventricle loading. Computerization allows bedside monitoring of this sophisticated assessment of right ventricle after loading.