From the Guidelines
Global longitudinal strain (GLS) on an echocardiogram is a crucial measurement for assessing cardiac function, particularly for detecting subtle cardiac dysfunction before changes in ejection fraction become apparent, with normal values typically ranging from -18% to -22% 1.
Importance of GLS
GLS is calculated using speckle-tracking echocardiography, which follows natural acoustic markers in the heart muscle as they move during contraction. This measurement provides a more sensitive assessment of cardiac function than traditional ejection fraction.
Clinical Applications
Some key points about GLS include:
- It is useful for monitoring patients receiving cardiotoxic medications, those with valvular heart disease, or individuals with cardiomyopathies 1.
- GLS is helpful for risk stratification and prognosis in various cardiac conditions, including heart failure 1.
- A cut-off value of -18% can be expected to indicate normal LV longitudinal systolic function, although magnitudes are vendor-dependent 1.
Measurement and Interpretation
GLS specifically measures the percentage of shortening of the left ventricle from diastole to systole. More negative numbers indicate better heart function.
Recent Recommendations
Recent guidelines and expert consensus documents emphasize the importance of integrating GLS into comprehensive echocardiographic evaluations to provide a more complete assessment of cardiac function 1.
From the Research
Definition of Global Longitudinal Strain
- Global Longitudinal Strain (GLS) is a measure of left ventricular function that can be obtained through speckle-tracking echocardiography 2.
- It is a systolic parameter that measures the deformation of the left ventricle in the longitudinal direction 2.
Normal and Abnormal Values
- The normal range of LV GLS is defined as -18% and lower (i.e., more negative), while abnormal values are defined as -16% or higher (i.e., less negative) 2.
- A borderline range is defined as -16 to -18% 2.
Clinical Utility
- GLS has been shown to be a more sensitive marker of LV dysfunction than LV ejection fraction alone and has prognostic impact in non-surgical cardiac populations 3.
- GLS can be used to evaluate subclinical LV dysfunction, RV dysfunction, atrial fibrillation, and sequential follow-up in patients with cardiotoxicity 2.
- GLS has been shown to be useful in predicting future deterioration of left ventricular function in heart failure patients with a recovered left ventricular ejection fraction 4.
- Changes in GLS values can be useful for the long-term risk stratification of patients hospitalized for heart failure with preserved ejection fraction (HFpEF) and persistently preserved LVEF 5.
Measurement and Variability
- GLS can be measured using 2-dimensional speckle-tracking echocardiography 3.
- The variation between different vendors is now small for global parameters, but regional strain measurement remains unreliable 2.
- Further research is needed to determine normal versus abnormal values for different surgical populations and to explore the potential treatment options that may modify and decrease surgical risk for those with abnormal GLS 3.