Fig. 2

Schematic representation of a framework of single-beat end-systolic left ventricular elastance (Ees) estimation by approximating the time-varying elastance curve as two linear functions. a Time-varying elastance curve (solid line) and two linear approximations (dashed line). b Estimated end-systolic pressure–volume loop (solid line). LV left ventricle, Ead elastance at the end of isovolumic contraction phase, Eed end-diastolic elastance, PEP pre-ejection period, ET ejection time, θiso and θej angles of approximated lines of isovolumic contraction phase and ejection phase, respectively, Pmax peak isovolumic pressure, Pad pressure at the end of isovolumic contraction phase, Ped end-diastolic pressure