Fig. 2

Bland and Altman plots of the respective first and tenth examination blocks for measurements of left ventricular diameter (a) and area (b) (end-diastolic marked as triangles, end-systolic marked as circles), both needed for calculation of ejection fraction (c). The plots show the measured differences between student and tutor (y-axis) depending on the respective average (x-axis). The precision increases for both the determination of the diameter and the area between the first and tenth examination block. The calculation of the ejection fraction also follows this trend. The solid lines represent the bias (mean), the dashed lines the limits of agreement (mean ± 1.96 SD). For comparability, the scales of the y-axes are identical for the first and tenth examinations