Figure 50-7 Myocardial oxygen consumption correlates with the left ventricular pressure-volume area (PVA). PVA is in the area of the pressure-volume (P-V) diagram that is circumscribed by the end-systolic P-V line (E-C), the end-diastolic P-V relation cure (D-A), and the systolic segment of the P-V trajectory (E-C-D-E). PVA consists of the external work (EW) performed during systole and the end-systolic elastic potential energy (PE) stored in the ventricular wall at end-systole. EW is the area within the P-V loop trajectory (A-B-C-D-A), and PE is the area between the end-systolic P-V line and the end-diastolic P-V relation curve to the left of EW (E-C-D-E). (Redrawn from Kameyama T, Asanoi H, Ishizaka S, et al: Energy conversion efficiency in human left ventricle. Circulation 85:988, 1992.)