Normal Left Ventricular Longitudinal Peak Systolic Strain Average
The normal left ventricular global longitudinal strain (GLS) average is between -18% and -22%, with a mean value of approximately -19.7% (more negative values indicate better function).
Understanding Left Ventricular Strain
Left ventricular (LV) longitudinal strain is a measure of myocardial deformation that assesses the function of longitudinal myocardial fibers, primarily located in the subendocardial layer. It is measured using speckle-tracking echocardiography (STE), which has become an important tool for evaluating subclinical cardiac dysfunction.
Normal Reference Values
According to comprehensive guidelines and meta-analyses:
- The normal range for LV global longitudinal strain (GLS) is -15.9% to -22.1%, with a mean of -19.7% (95% CI, -20.4% to -18.9%) 1
- Values better than (more negative than) -18% are generally considered normal 2
- Values between -16% and -18% are considered borderline 2
- Values worse than (less negative than) -16% are considered abnormal 2
The European Association of Cardiovascular Imaging (EACVI) guidelines indicate that LV GLS worse than -18% should be considered abnormal 3.
Factors Affecting Strain Measurements
Several factors can influence strain measurements:
- Blood pressure: Meta-regression analysis has shown that systolic blood pressure is significantly associated with variations in normal GLS values 1
- Heart rate: An inverse correlation exists between heart rate and GLS values (higher heart rates associated with lower absolute GLS values) 4
- LV end-diastolic length: GLS is independently and inversely related to LV end-diastolic length 4
- Age and gender: These have less consistent effects on strain measurements 1
Clinical Applications of Strain Measurement
Strain imaging provides valuable information in various clinical scenarios:
- Subclinical LV dysfunction: Detecting early cardiac dysfunction in patients with preserved ejection fraction
- Heart failure with preserved ejection fraction (HFpEF): GLS is often reduced despite normal LVEF 3
- Cardiomyopathies: Distinguishing between physiological LVH in athletes from pathological LVH 3
- Valvular heart disease: Monitoring LV function in conditions like aortic stenosis 5
- Cardiotoxicity monitoring: Sequential follow-up during cardiotoxic treatments 2
Technical Considerations
When interpreting strain measurements, consider:
- Vendor variability: Although reduced with modern software, some differences between vendors may exist
- Image quality: High-quality images are essential for accurate strain measurements
- Regional vs. global measurements: Global measurements are more reliable than regional strain values 2
- Observer variability: Interobserver correlations for GLS (r = 0.71) are moderate compared to other measures of longitudinal function 4
Comparison with Other Measures of LV Function
- GLS detects subtle changes in LV function before changes in ejection fraction become apparent
- GLS correlates with other measures of longitudinal function such as mitral annular plane systolic excursion (MAPSE) and tissue Doppler-derived systolic velocity (s') 4, 5
- In some clinical scenarios, MAPSE may provide similar diagnostic information to GLS and can be used when GLS is not available 5
Understanding normal strain values is essential for proper interpretation of cardiac function and early detection of subclinical myocardial dysfunction.