End-diastolic and end-systolic volumes for the load alteration sequences are shown here, grouped by beat in the sequence. All the first beats are grouped together, all the second beats, etc. The change in load, as demonstrated by volumes for the sequences collected during experimental alteration in inotropic status, is clearly shown. These load ranges correspond to the grouped tissue velocity and strain measures in later figures. Data are presented as mean ± SEM, n = 13. Filled diamond = Control; Open triangle = Adrenaline; Open square = Beta-blockade. EDV = end diastolic volume; ESV = end systolic volume. # p < 0.05 with repeated measures ANOVA.