What is the normal range for strain in echocardiography (echo)

Normal Ranges for Strain in Echocardiography

The normal range for left ventricular global longitudinal strain (GLS) is -20% to -16%, with values less negative than -20% (i.e., <20% in absolute value) considered abnormal, while for right ventricular free wall strain, a value less negative than -20% is likely abnormal. 1

Left Ventricular Strain Normal Values

Global Longitudinal Strain (GLS)

• Normal LV GLS range: -20% to -16% (more negative values indicate better function)
• Pooled data from the American Society of Echocardiography and European Association of Cardiovascular Imaging suggests that a peak GLS in the range of -20% can be expected in a healthy person 1
• Values less negative than -16% (i.e., >-16%) are considered abnormal
• Values between -16% and -18% are considered borderline 2

Circumferential and Radial Strain

• Normal global circumferential strain range: approximately -23.3% (95% CI: -24.6% to -22.1%) 3
• Normal global radial strain range: approximately 47.3% (95% CI: 43.6% to 51.0%) 3

Right Ventricular Strain Normal Values

RV Free Wall Strain

• Normal RV free wall strain: approximately -29% 1
• Values less negative than -20% (i.e., <20% in absolute value) are likely abnormal 1

RV Free Wall and Septal Strain

• Normal RV free wall and septal strain: approximately -21% 1

Factors Affecting Strain Measurements

Technical Considerations

• Vendor-specific differences exist, making universal normal values challenging to establish 1
• Image quality affects strain measurements - proper acquisition technique is crucial
• Proper placement of reference points is essential - placing basal reference points too low on the atrial side of the tricuspid annulus can result in artificially low strain values 1

Physiological Factors

• Age: Strain values generally decrease with age 1, 4
• Sex: Women typically have slightly higher absolute values of GLS than men 1, 4
• Blood pressure: Higher systolic blood pressure is associated with lower strain values 3

Clinical Applications of Strain

Key Clinical Uses

• Detection of subclinical LV dysfunction in patients with preserved ejection fraction 2
• Early detection of cardiotoxicity during cancer therapy 1
• Prognostic assessment in various cardiovascular conditions 1
• Risk stratification in patients with recovered left ventricular function 5

Monitoring During Cancer Therapy

• A 10-15% early reduction in GLS during cancer therapy appears to be the most useful parameter for predicting cardiotoxicity 1
• GLS can detect preclinical changes in LV systolic function before a decrease in ejection fraction 1

Important Caveats

• Regional strain measurements remain less reliable than global measurements 2
• Strain values should be interpreted in the context of the specific vendor software used 6
• Until universal standards are established, interpretation of strain values should take into account methodology and vendor-specific reference values 1
• Follow-up examinations should use the same equipment, tracing methodology, and software for reliable comparison 1

When interpreting strain values, it's essential to consider the specific chamber being assessed, the measurement technique, and patient-specific factors such as age and sex to ensure accurate clinical assessment.