The left panel shows a schematized left ventricular (LV) pressure–volume loop from a patient with primary systolic failure. A normal LV pressure–volume loop (solid loop) is shown on the left portion of the curve; the transition to inotropic failure (dashed loop) is shown on the right. Systolic failure is manifest as an increase in LV end-systolic volume and as a reduction in the extent of shortening (stroke volume). LV end-diastolic pressure (LVEDP) is increased because LV volume is increased. As indicated by the arrow, the diastolic portion of the pressure–volume loop has simply shifted to the right, along the same diastolic pressure–volume relationship; thus, no change in the distensibility of the left ventricle has occurred. The right panel shows an LV pressure–volume loop from a patient with primary diastolic failure (dashed loop). Note that the LVEDP is the same as that in the patient with primary inotropic failure, as denoted by the heavy dots on both pressure–volume loops. In the right panel, however, this is caused by an upward shift of the LV diastolic pressure–volume relationship (arrows), which indicates a decrease in LV diastolic distensibility such that a higher diastolic pressure is required to achieve the same diastolic volume. In this patient, no change in end-diastolic volume or systolic shortening has occurred. From Lorell BH. Left ventricular diastolic pressure-volume relations: understanding and managing congestive heart failure. Heart Failure. 1988;4:206-223. Copyright 2011. Reprinted with permission of John Wiley & Sons, Inc. Source: Chapter 26. Pathophysiology of Heart Failure, Hurst's The Heart, 13e Citation: Fuster V, Walsh RA, Harrington RA. Hurst's The Heart, 13e; 2011 Available at: https://accessmedicine.mhmedical.com/DownloadImage.aspx?image=/data/Books/hurs13/hurs13_c026f006.gif&sec=40285262&BookID=376&ChapterSecID=40279753&imagename= Accessed: December 18, 2017 Copyright © 2017 McGraw-Hill Education. All rights reserved