Echocardiographic Measurement of Left Atrial Strain as a Tool for Assessing Left Atrial Function and Geometric Change

The left atrium (LA) serves as a reservoir of blood draining from the pulmonary veins during ventricular systole, a conduit of blood during ventricular diastole, and a booster pump of blood flow during atrial contraction. Normal LA function is important in maintaining adequate cardiac performance, and it becomes abnormal in various cardiac or extra-cardiac conditions. The abnormality of LA function can induce geometric changes, which results in the increase of the size and volume of the LA, and it has been non-invasively assessed by measuring the LA size or volume by echocardiography. The previous studies have shown that the LA size or volume is a powerful predictor of cardiovascular outcomes in various cardiac diseases, and thus, can be used as an imaging biomarker of cardiovascular disease or outcomes. Strain is a measure of deformation, and strain rate is a rate of such deformation. Strain echocardiography has been the most widely used tool to evaluate the ventricular myocardial mechanics in the field of echocardiography, during the last decade. Since the normal longitudinal LA strain values were first described in 2006, recent studies have suggested that LA strain or strain rate can be measured either by a tissue Doppler image or 2 dimensional (2D) speckle tracking image based echocardiography, and these measurements are useful tools to evaluate the global or regional LA function. The Editorial