From the Guidelines
A Global Longitudinal Strain (GLS) value of 15% is significantly lower than the expected normal range, indicating impaired left ventricular systolic function. Normal GLS values are typically considered to be around -18% to -22% 1, with the negative sign often dropped in discussion, suggesting that a GLS of 15% represents a notable reduction in cardiac contractility. This finding implies that the heart muscle is not contracting as efficiently as it should, which could be indicative of underlying cardiac issues such as coronary artery disease, hypertension, valve disease, or cardiomyopathy, despite potentially normal ejection fraction values. Given the sensitivity of GLS in detecting subclinical myocardial dysfunction before more overt changes occur 1, patients with a GLS of 15% may benefit from further cardiac evaluation and potentially closer monitoring, lifestyle modifications, or adjustments in medication, depending on the clinical context and the specific underlying cardiac condition. It's crucial to note that GLS measurements should be made with consideration of the equipment and software used, as well as the patient's age and gender, due to variations in normal values 1. Early detection of reduced strain can allow for timely intervention, potentially preventing the progression to more severe cardiac dysfunction. Key considerations in interpreting GLS values include the use of consistent methodology and equipment for serial assessments 1, as intervendor and inter-software variability can impact results.
From the Research
Global Longitudinal Strain (GLS) of 15
- A GLS of -15% is generally considered to be within the normal range or slightly reduced, depending on the context and population being studied 2, 3, 4.
- In patients with heart failure with preserved ejection fraction (HFpEF), a GLS of -15.7% was reported, indicating some degree of longitudinal systolic dysfunction 2.
- In a study of patients undergoing heart valve surgery with preserved left ventricular ejection fraction, a GLS of -16% was used as a cutoff to distinguish between impaired and normal GLS groups 4.
- A GLS of -15% or lower may be associated with worse cardiovascular outcomes and increased risk of adverse events, such as prolonged mechanical ventilation and need for pharmacologic hemodynamic support after cardiac surgery 3, 4.
- It is essential to consider the specific clinical context and population being studied when interpreting GLS values, as the normal range and cutoff values may vary depending on the study and patient characteristics 5, 2, 3, 4, 6.
Comparison with Other Studies
- Other studies have reported similar findings, with GLS values ranging from -12% to -18% in patients with various cardiovascular conditions, including hypertrophic cardiomyopathy, aortic stenosis, and COVID-19 5, 2, 3, 4, 6.
- The optimal cutoff value for GLS may vary depending on the specific condition and population being studied, highlighting the need for further research to establish standardized cutoff values and interpretation guidelines 2, 3, 4.
Clinical Implications
- A GLS of 15 may indicate some degree of longitudinal systolic dysfunction, which can be associated with increased risk of adverse cardiovascular events and worse outcomes 2, 3, 4.
- Clinicians should consider GLS values in conjunction with other clinical and echocardiographic parameters to assess cardiac function and guide management decisions 5, 2, 3, 4, 6.