Figure 4. Histograms illustrating changes (Delta) in end-systolic segment length (ESL) during a decrease and increase in left ventricular afterload produced by inferior vena caval (IVC) occlusion (left) and phenylephrine infusion (right), respectively, in the conscious state (top panel) and during isoflurane (middle panel) and halothane (bottom panel) anesthesia before (hatched bar; normal) and after (solid bar; cardiomyopathy) the development of pacing-induced cardiomyopathy.^aSignificantly different from normal myocardium.