What does a longitudinal strain of -20% of the left ventricle indicate?

Left Ventricular Longitudinal Strain of -20%: Interpretation

A left ventricular global longitudinal strain (GLS) of -20% is within the normal range and indicates preserved systolic function of the left ventricle. 1, 2

Understanding the Measurement

• Global longitudinal strain measures the maximal deformation (shortening) of the left ventricular myocardium during systole, averaged over the entire ventricle and expressed as a percentage. 1

• Because strain represents compression/shortening, it is expressed as a negative number—values closer to zero (less negative) represent worse function, while more negative values indicate better function. 1

• The normal range for LV GLS has been defined as -18% and lower (more negative), with values of -16% or higher (less negative) considered abnormal, and -16% to -18% being borderline. 2

• A meta-analysis of normal subjects found GLS values ranging from -15.9% to -22.1%, with a mean of -19.7% (95% CI: -20.4% to -18.9%). 3

Clinical Significance of -20%

• Your value of -20% falls comfortably within the normal range, indicating normal longitudinal contractile function of the left ventricle. 2, 3

• This measurement reflects the function of the subendocardial (inner layer) longitudinal myocardial fibers, which are particularly sensitive to early cardiac dysfunction. 1

• GLS is more sensitive than ejection fraction for detecting subclinical left ventricular dysfunction, making it valuable even when ejection fraction appears normal. 1, 2

Important Context

• Blood pressure at the time of measurement can affect strain values—higher systolic blood pressure is associated with less negative (worse) strain values. 3

• Strain values may vary slightly between different ultrasound equipment vendors, though this variation has decreased with modern standardization efforts. 2

• Age and systolic blood pressure can influence longitudinal strain, with values becoming less negative (decreasing) with increasing age and blood pressure. 4

Clinical Applications

• A normal GLS of -20% effectively rules out significant left ventricular systolic dysfunction and suggests preserved myocardial contractility. 2, 5

• In patients with chest pain, a GLS value better than -16.5% (more negative) has high negative predictive value (92%) for excluding severe coronary disease. 5

• This normal value indicates that the longitudinal myocardial fibers are contracting appropriately, which is reassuring for overall cardiac function. 1