Normal reference ranges for echocardiography: do we really need more?

Echocardiography is the most widely used non-invasive cardiac imaging for assessing the cardiac structure and function. Echocardiography has the advantage of low cost, no radiation risk, and great availability. However, as for any diagnostic test, its interpretation depends on its ability to accurately detect abnormalities.1 Actually, the definition of ‘abnormal’ relies on the definition of ‘normal’ and differs according to age, gender, body surface area, and ethnicity.2–4 Currently, available echocardiographic ‘reference values’ that define ‘normality’ are mostly based on cross-sectional observations and refer to earlier studies obtained in the 1970–80s from North American cohorts, which do not reflect the diversity of the world's population.5Establishing ‘normal’ reference values for echocardiography represents a major need in the field of cardiology.6 Needless to say that the targeted population and the method used to collect the data are vital. Regarding the target population, if not otherwise specified, a standard ‘reference’ range generally denotes the one in ‘healthy’ individuals, or without any known condition that directly affects the ranges being established. Regarding the method used, prospective studies are very welcome but still scanty. Therefore, the compilation of large databases can be used …