Fig. 1
From: Non-invasive quantification of pressure–volume loops in patients with Fontan circulation
A Schematic pressure–volume (PV) diagram. The ventricular pressure (P) is plotted against the ventricular volume (V) at multiple time points during a single cardiac cycle. Stroke volume (SV) is calculated as end-diastolic volume (EDV) minus end-systolic volume (ESV). The PV loop area represents stroke work (SW), and the grey triangle corresponds to mechanical potential energy (PE). The slope between V0, the pressure at zero volume, and the point of end-systolic pressure–volume relation (ES PVR), also called end-systolic elastance (Ees), defines contractility. The method for non-invasive PV loops approximates V0 to be zero. The negative slope of the line between the point of ES PVR and the point at end-diastolic volume and zero pressure represents the arterial elastance (Ea). B Representative non-invasive PV loops in a patient with Fontan circulation (grey) and in a healthy volunteer (dashed line) with same body surface area. The patient with Fontan circulation has similar blood pressure and EDV but higher ESV and thus lower SV than the control. This results in lower stroke work and higher potential energy