Clinical Implications of GLS -16.2%
A GLS of -16.2% indicates mild left ventricular systolic dysfunction and warrants close monitoring, as this value falls just below the abnormal threshold and signals early subclinical myocardial impairment that precedes overt heart failure. 1
Understanding the Measurement
GLS of -16.2% is abnormal. The established normal range for GLS is -18% or lower (more negative), with values of -16% or higher (less negative) considered abnormal, and -16% to -18% representing a borderline zone. 2
This measurement reflects dysfunction of the subendocardial longitudinal myocardial fibers, which are the most sensitive to early cardiac injury and typically affected before ejection fraction declines. 3
Values closer to zero (less negative) represent worse myocardial function, while more negative values indicate better contractility. 3
Clinical Significance and Risk Stratification
This patient has subclinical left ventricular dysfunction that carries prognostic implications:
Values < -16% indicate mild depression of GLS and represent early LV subclinical dysfunction that may not yet be apparent on ejection fraction measurement. 1
GLS is more sensitive than ejection fraction for detecting early myocardial dysfunction, often identifying abnormalities months before EF declines. 1
In the general population, reduced GLS independently predicts long-term risk of heart failure, acute myocardial infarction, and cardiovascular death, even after adjusting for traditional risk factors and ejection fraction. 4
Each 1% decrease in GLS (becoming less negative) is associated with increased cardiovascular mortality risk. 5
Specific Clinical Contexts
Cardio-oncology Surveillance
A relative percentage reduction of GLS >15% from baseline is considered abnormal and a marker of early cardiotoxicity during cancer therapy. 1
GLS <-19% has been shown to predict subsequent cardiotoxicity in patients receiving trastuzumab, and a ≥11% relative reduction in GLS predicts trastuzumab-associated cardiac dysfunction. 1
In cancer patients, a GLS value of -16.2% would be classified as "Low-GLS" (defined as <-16%) and indicates increased risk for cancer therapy-related cardiac dysfunction. 6
Heart Failure Populations
In chronic heart failure cohorts, GLS of -16.2% would fall within the range typical of symptomatic patients (stages C/D heart failure, where mean GLS is approximately -15.5%). 5
GLS independently predicts cardiac mortality even after adjusting for NT-proBNP levels, clinical status, and cardiac structure/function. 5
Valvular Heart Disease
- In aortic stenosis and mitral regurgitation, reduced GLS identifies subclinical LV dysfunction that may warrant earlier intervention, even when ejection fraction remains preserved. 2
Recommended Clinical Actions
Immediate steps:
Confirm the measurement by repeating echocardiography with the same equipment vendor within 2-3 weeks, as vendor variability can affect absolute values (though this is now minimal for global parameters). 1
Ensure image quality was adequate and that the measurement was performed by experienced personnel, as GLS requires proper expertise for accurate interpretation. 1
Document the baseline value for future comparison, as serial changes are more clinically meaningful than single measurements. 1
Diagnostic workup:
Investigate underlying etiologies: ischemic heart disease, hypertension, cardiomyopathy, valvular disease, or cardiotoxic exposures. 1
Consider cardiac biomarkers (troponin, NT-proBNP) to assess for active myocardial injury or neurohormonal activation. 1
Evaluate diastolic function parameters (E/e', left atrial size, deceleration time), as diastolic dysfunction commonly accompanies reduced GLS. 1
Follow-up strategy:
Implement serial GLS monitoring every 3-6 months to detect progression, as worsening GLS over time indicates pathological deterioration. 1
Use the same echocardiography equipment for longitudinal follow-up to facilitate accurate interpretation of changes. 1
Initiate or optimize guideline-directed medical therapy if heart failure risk factors are present (ACE inhibitors/ARBs, beta-blockers). 1
Important Caveats
GLS values are not applicable to patients currently receiving inotropic agents or mechanical circulatory support, as these interventions alter the measurement. 1
Regional strain measurements remain unreliable across vendors and should not be used for clinical decision-making; only global parameters are sufficiently standardized. 2
In post-cardiac surgery patients, septal strain may be artifactually reduced due to paradoxical septal motion, making lateral wall assessment more reliable. 1
Sex differences exist: GLS appears to be a stronger prognosticator in men than women in general population studies. 4
The measurement requires adequate image quality with clear endocardial border definition; consider contrast enhancement if borders are suboptimal. 1