Figure 4a. (a) Bland-Altman plot for measurements of total stroke volume (SV) of left ventricle compared with forward stroke volume in aorta in 62 patients with intact cardiac valves. Differences are plotted against the mean of the two stroke volume measurements. Dashed line = mean difference, dotted lines = 2 standard deviations. (b) Linear regression analysis for measurements of total stroke volume (SV) of left ventricle compared with forward stroke volume in aorta in 62 patients with intact cardiac valves. Solid line = regression curve, dashed lines = 95% CIs. There is substantial agreement with no systematic error between total and forward stroke volume measured at electron-beam CT (intraclass correlation coefficient, rI = 0.93).