The hemodynamic evaluation of the pulmonary circulation normally includes the measurements of mean pulmonary artery pressure and a calculation of pulmonary vascular resistance (PVR). The definition of PVR can be improved by the measurements of pulmonary vascular pressures at several levels of flow to derive a pressure-flow line, and the site of PVR can be identified by the analysis of pulmonary artery pressure decay curves after balloon occlusion. An analysis of the morphology of pulmonary

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... y pressure and flow waves informs about right ventricular (RV) hydraulic load. As pulmonary hypertension is clinically a right heart failure syndrome, it is important to measure the coupling of RV to pulmonary arterial function. This can be done using a single beat method with sampling and synchronization of instantaneous pulmonary artery flow and RV pressure to calculate a ratio of end-systolic to arterial elastances. The optimal value of this ratio is depressed in minimally symptomatic pulmonary arterial hypertension patients, indicating pending right heart failure.