The importance of the right ventricle is consistently underestimated. In conventional thinking about the cardiovascular system, the focus is invariably the function of the left ventricle. It is to be applauded that this study of Clark et al recognises the importance of the right ventricle and attempts to quantify measures of function in healthy term and preterm babies.

One reason for the absence of data about the function of the right ventricle is the lack of consistent landmarks that allow standardisation of function measures. Even in the left ventricle, interpretation of myocardial function measures is fraught with problems. In preterm babies, the traditional M mode measures, such as fractional shortening, are of limited use because of the reduced movement of the ventricular septum.¹ An often ignored basic truth about the cardiovascular system is that a measurement at any one …