Figure 3. Histograms that depict the peak rate of segment lengthening during rapid ventricular filling (dL/dt^E; top panel) and atrial systole (dL/dtA; middle panel) and the ratio of dL/dt^Eto dL/dt^A(dL/dt-E/A; bottom panel) in the conscious state before (C; open bar) and after pacing (P) and during 1.1, 1.4, and 1.7 MAC (end-tidal concentration) isoflurane (hatched bars) and halothane (solid bars).^aSignificantly (P < 0.05) different from P;^bSignificantly (P <0.05) different from 1.1 MAC;^cSignificantly (P < 0.05) different from 1.4 MAC.