Fig. 2

Example of left (LV) and right (RV) ventricular pressure–volume loops (animal model). LV loops are normally rectangular with a well-defined upper left corner corresponding to end-systole, which occurs shortly after maximal pressure is reached. In contrast, under normal, low-pressure conditions the RV loop is more triangular with a less well-defined upper left corner that occurs well after maximal pressure is reached. However, in the setting of pulmonary hypertension, the RV loop transitions to a morphology more similar to a normal LV pressure–volume loop. Data were obtained during an experimental study of progressive pulmonary vasoconstriction under a protocol approved by the institutional animal care and use committee. The figure is reproduced with permission from the PeriOperative Quality Initiative (POQI)