Variability of longitudinal strain measurements: levelling the playing field.

Speckle tracking echocardiography offers a unique opportunity to evaluate myocardial function, and global longitudinal strain (GLS) is currently recommended as a measurement of global left ventricular function. To facilitate clinical applicability of the method, collective efforts have been made to standardise strain measurements and to raise awareness of the potential sources of variability. The purpose of this review is to familiarise the reader with the most common sources of variability of longitudinal strain measurements and detail the possible measures to increase the accuracy and reproducibility of strain parameters.