The end-systolic pressure-volume relationship (ESPVR). Suga and Sagawa were the first to use simultaneous LV pressure-volume measurements. These Authors, searching for a preload and afterload independent contractility index, measured pressure-volume loops during sudden preload and afterload changes. The upper left corners of the loops (C, C1, C2, C... points) define the LV end-systolic pressure-volume relation (ESPVR). ESPVR predicts the end-systolic volume in a heart with constant contractility when end-systolic pressure changes, and ultimately predicts the left ventricle ability to empty for different afterload values. The slope of the ESPVR line is the end-systolic elastance (Ees). In the clinical setting it is difficult to generate the end-systolic pressure-volume relationship (ESPVR) free of changes in reflex-mediated variations in contractility. It also requires a means to measure pressure and volume accurately and simultaneously.