Global Longitudinal Strain
A measurement of the relative shortening of the left ventricular myocardium along its long axis during systole, derived from speckle tracking on standard 2D echo loops.
GLS quantifies myocardial deformation as a percentage shortening from end-diastole to end-systole, averaged across all left-ventricular segments. Normal GLS values are typically more negative than −18% (ASE / EACVI consensus 2018).
GLS is more sensitive than LVEF for detecting early systolic dysfunction. It is the primary surveillance parameter for cardiotoxicity from cancer therapy, for early HFpEF detection, and for sub-clinical dysfunction in cardiomyopathies.
Historically vendor-dependent (different speckle-tracking algorithms produced incomparable values), GLS measurement is now increasingly standardised, AI-assisted strain is independent of vendor platform and reduces measurement variability.