Figure 7-12 Histograms illustrate total arterial compliance (C, top panel), total arterial resistance (R, middle panel), and characteristic aortic impedance (Z_C , bottom panel) in the conscious state and during 1.1 and 1.5 minimum alveolar concentrations (MACs) of isoflurane in dogs before (red bars) and after (gray bars) the development of pacing-induced cardiomyopathy. a, Significantly (P < .05) different from normal myocardium. (Adapted from Hettrick DA, Pagel PS, Kersten JR, et al: The effects of isoflurane and halothane on left ventricular afterload in dogs with dilated cardiomyopathy. Anesth Analg 85:979–986, 1997.)