Normal Range for Longitudinal Strain in a Healthy Heart
The normal range for global longitudinal strain (GLS) in a healthy heart is greater than -18% (more negative), with values between -16% and -18% considered borderline, and values ≤-16% (less negative) considered abnormal. 1, 2
Understanding Global Longitudinal Strain
Global longitudinal strain is a sensitive echocardiographic parameter that measures myocardial deformation and provides valuable information about cardiac function. It offers several advantages over traditional ejection fraction measurements:
- Detects subclinical myocardial dysfunction before ejection fraction decline
- More sensitive for early identification of cardiac abnormalities
- Provides incremental predictive value in patients undergoing echocardiography
Reference Ranges and Interpretation
| Strain Value | Interpretation |
|---|---|
| > -18% (more negative) | Normal |
| -16% to -18% | Borderline |
| ≤ -16% (less negative) | Abnormal |
These reference ranges are based on the European Association of Cardiovascular Imaging (EACVI) guidelines 1. A value worse than -16% (less negative) should raise concern for myocardial pathology 3.
Clinical Applications of GLS Measurement
GLS measurements have significant clinical utility in:
- Detecting subclinical LV dysfunction in patients with preserved ejection fraction
- Monitoring cardiotoxicity from chemotherapy
- Evaluating right ventricular function in pulmonary hypertension
- Assessing cardiac function in various cardiomyopathies
- Serial monitoring of cardiac function over time
Important Considerations When Measuring GLS
When interpreting GLS values, several factors should be considered:
- Vendor variability: Measurements should be performed using the same vendor's equipment for serial assessments due to inter-vendor variability 1
- Image quality: Poor image quality can significantly affect the accuracy of GLS measurements
- Loading conditions: GLS may be affected by loading conditions and heart rate 1
- Exercise response: In healthy individuals, GLS increases during exercise, with studies showing values increasing from approximately -20.4% at rest to -23.7% during submaximal exercise 4
Red Flags in GLS Interpretation
- A GLS value of -14% indicates moderate myocardial dysfunction requiring further clinical evaluation 1
- A GLS value of -8% represents severe myocardial dysfunction associated with higher risk of adverse cardiac events 1
- In athletes, a GLS value worse than -16% should raise concern for myocardial pathology, even with normal ejection fraction 3
Pitfalls to Avoid
- Relying solely on ejection fraction to assess cardiac function, as GLS is more sensitive for detecting subtle changes
- Using different vendor equipment for serial measurements, which can lead to inconsistent results
- Failing to consider loading conditions and heart rate when interpreting GLS values
- Overreliance on regional strain measurements, which remain less reliable than global measurements
By understanding the normal range and clinical significance of GLS, clinicians can better identify early cardiac dysfunction and monitor disease progression or treatment response in various cardiac conditions.