Fig. 8

Bland–Altman plots exhibiting intra-observer variability for cardiac axis (CAx) and cardiothoracic ratio (CTR) measurements. Blue dotted line: mean difference; red dotted line: 95% limits of agreement. (a) CAx measurements by senior sonographer; (b) CTR measurements by senior sonographer; (c) CAx measurements by intermediate sonographer; (d) CTR measurements by intermediate sonographer; (e) CAx measurements by junior sonographer; (f) CTR measurements by junior sonographer