Clinical Implications of Reduced Left Ventricular Systolic Function

Understanding the Measurement

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, according to the European Heart Journal 1
Values < -16% indicate mild depression of GLS and represent early LV subclinical dysfunction that may not yet be apparent on ejection fraction measurement, as reported by the European Heart Journal 1

GLS is more sensitive than ejection fraction for detecting early myocardial dysfunction, often identifying abnormalities months before EF declines, as stated by the American College of Cardiology 2, 3
A relative percentage reduction of GLS >15% from baseline is considered abnormal and a marker of early cardiotoxicity during cancer therapy, according to the European Heart Journal 4

Confirm the measurement by repeating echocardiography with the same equipment vendor within 2-3 weeks, as vendor variability can affect absolute values, as recommended by the European Heart Journal 4, 5
Implement serial GLS monitoring every 3-6 months to detect progression, as worsening GLS over time indicates pathological deterioration, as suggested by the European Heart Journal 6
Initiate or optimize guideline-directed medical therapy if heart failure risk factors are present, such as ACE inhibitors/ARBs, beta-blockers, as recommended by the European Heart Journal 4

GLS values are not applicable to patients currently receiving inotropic agents or mechanical circulatory support, as these interventions alter the measurement, as noted by the European Heart Journal 1
In post-cardiac surgery patients, septal strain may be artifactually reduced due to paradoxical septal motion, making lateral wall assessment more reliable, as reported by the European Heart Journal 6, 7

Global longitudinal strain measures the maximal deformation (shortening) of the left ventricular myocardium during systole, averaged over the entire ventricle and expressed as a percentage, with a normal range defined by values such as -20% indicating preserved systolic function of the left ventricle 8
Because strain represents compression/shortening, it is expressed as a negative number—values closer to zero (less negative) represent worse function, while more negative values indicate better function 8

This measurement reflects the function of the subendocardial (inner layer) longitudinal myocardial fibers, which are particularly sensitive to early cardiac dysfunction 9
GLS is more sensitive than ejection fraction for detecting subclinical left ventricular dysfunction, making it valuable even when ejection fraction appears normal 10

A normal GLS value, such as -20%, indicates that the longitudinal myocardial fibers are contracting appropriately, which is reassuring for overall cardiac function 9, 10

Normal GLS ranges from -18% to -22%, with values between -16% to -18% considered borderline, and anything above -16% classified as abnormal, according to the European Society of Cardiology 11
A GLS value of -16.2% falls into the borderline-to-mildly abnormal range, indicating early subclinical left ventricular dysfunction, as suggested by guidelines from the European Heart Journal 11, 12

Significant vendor variability in GLS measurements exists between different ultrasound machines and software versions, which can lead to cautious interpretation of borderline values, as noted by the European Heart Journal 11, 12
In certain populations, such as athletes, slightly reduced GLS values can represent normal physiologic adaptation rather than pathology, according to the American College of Cardiology 13, 14

The clinical context, including recent viral illness, athletic training status, or other conditions, can explain borderline GLS values and should be discussed with a cardiologist, as recommended by the American College of Cardiology 13, 14
A single borderline GLS value does not necessarily indicate disease, especially if the patient is asymptomatic, has no cardiac risk factors, and has a normal ejection fraction, as stated by the American College of Cardiology 13, 14