What is the significance of a left ventricular global longitudinal strain (LV GLS) of –17.5% and what management is recommended?

LV GLS of -17.5% Indicates Borderline Left Ventricular Dysfunction Requiring Clinical Correlation and Potential Cardioprotective Intervention

A left ventricular global longitudinal strain (LV GLS) of -17.5% falls in the borderline/mildly abnormal range and warrants comprehensive cardiac evaluation, assessment for underlying cardiac pathology, and consideration of cardioprotective therapy depending on clinical context.

Understanding the Significance

Normal vs. Abnormal Thresholds

According to European Association of Cardiovascular Imaging guidelines, normal LV longitudinal systolic function is defined as GLS values more negative than -18% 1. Your value of -17.5% falls just short of this threshold, placing it in the borderline zone.

The classification framework is:

• Normal: GLS ≤ -18% (more negative)
• Borderline: GLS -16% to -18%
• Mildly abnormal: GLS > -16% but < -10%
• Severely abnormal: GLS ≥ -10%

Your value of -17.5% sits at the upper limit of borderline 2. Recent research confirms the normal range as -18% and lower (more negative), with abnormal defined as -16% or higher (less negative), and -16% to -18% being borderline 3.

Clinical Implications

This borderline value represents subclinical left ventricular dysfunction - meaning the heart's longitudinal contractile function is mildly impaired even if ejection fraction appears normal 1. GLS detects myocardial dysfunction earlier than ejection fraction because it assesses the function of subendocardial longitudinal fibers, which are the first to be affected by various cardiac insults.

Recommended Management Algorithm

Step 1: Verify Technical Factors

Before clinical action, confirm:

• Image quality was adequate - poor tracking can artificially reduce GLS values
• Same vendor software should be used for serial measurements (vendor-dependent variations exist, though contemporary software shows smaller differences) 4
• Heart rate and blood pressure at time of measurement - these affect strain values
• Patient characteristics: Female sex typically shows more negative (better) GLS values; higher heart rates reduce GLS magnitude 4

Step 2: Comprehensive Cardiac Assessment

Mandatory additional evaluations 1:

• Complete echocardiographic assessment:

  • LV ejection fraction (3D preferred for accuracy)
  • LV volumes and dimensions
  • Diastolic function parameters (E/e' ratio, e' velocity, LA volume index)
  • Regional wall motion abnormalities (always pathologic)
  • RV function assessment
  • Estimated pulmonary artery systolic pressure

• Clinical evaluation:

  • Symptoms: dyspnea, exercise intolerance, peripheral edema, rapid weight gain
  • NYHA/functional class
  • Cardiovascular risk factors
  • Family history of cardiomyopathy

• Cardiac biomarkers:

  • NT-proBNP or BNP
  • High-sensitivity troponin (especially if cardiotoxic therapy exposure)

Step 3: Identify Underlying Etiology

Common causes of borderline/reduced GLS with preserved LVEF 1, 2:

• Heart failure with preserved ejection fraction (HFpEF) - GLS is often the first abnormality
• Cardiotoxicity from cancer therapy (anthracyclines, trastuzumab, immune checkpoint inhibitors)
• Valvular heart disease (especially aortic stenosis, mitral regurgitation) - GLS predicts postoperative recovery
• Hypertrophic cardiomyopathy - early stages show reduced longitudinal strain despite preserved EF
• Infiltrative cardiomyopathies (amyloidosis, sarcoidosis)
• Coronary artery disease - ischemia or prior infarction
• Hypertension with LV hypertrophy

Step 4: Risk Stratification

Your -17.5% value has prognostic implications:

GLS is independently associated with cardiac mortality in heart failure patients, even after adjusting for clinical status, cardiac structure/function, and NT-proBNP levels 5. Values in the borderline range indicate increased cardiovascular risk compared to normal values.

Step 5: Treatment Decisions

For asymptomatic patients with borderline GLS (-17.5%) 6:

1. If receiving cardiotoxic cancer therapy:

   • Consider initiating cardioprotective treatment with ACE inhibitor/ARB with or without beta-blocker
   • Repeat GLS measurement every 3 months or sooner if symptoms develop
   • Monitor cardiac biomarkers based on therapy's cardiotoxicity risk
   • Do not alter life-saving cancer treatment based solely on GLS changes

2. If valvular heart disease present 1:

   • GLS helps predict postoperative LV function recovery
   • May influence timing of surgical intervention
   • Serial monitoring recommended

3. If suspected HFpEF 1:

   • Comprehensive diastolic function assessment mandatory
   • Optimize management of hypertension, diabetes, obesity
   • Consider guideline-directed medical therapy (SGLT2 inhibitors have Class I recommendation for HFpEF)

4. If no clear etiology identified:

   • Cardiology consultation recommended
   • Consider advanced imaging (cardiac MRI) to assess for fibrosis, infiltration, or subtle structural disease
   • Serial echocardiography in 3-6 months to assess trajectory

Critical Pitfalls to Avoid

1. Don't dismiss borderline values - GLS of -17.5% is not normal and requires explanation and follow-up
2. Don't rely on LVEF alone - ejection fraction may remain normal while GLS deteriorates, missing early dysfunction 1, 2
3. Don't compare values across different vendors without caution - though improving, some variation persists 4
4. Don't measure regional strain for clinical decisions - only global parameters are reliable; regional measurements remain unreliable 3
5. Don't use GLS in isolation - integrate with clinical context, biomarkers, and other echocardiographic parameters

Specific Context Considerations

In cancer patients receiving cardiotoxic therapy 7, 6, 8:

• A relative decrease in GLS >15% from baseline is the recommended cut-off for suspected cardiotoxicity
• If baseline GLS was normal (e.g., -20%), your current -17.5% represents a 12.5% relative reduction - approaching the threshold for concern
• Early cardioprotective intervention can prevent progression to overt LV dysfunction

In athletes 9:

• Normal GLS ranges from -16% to -22% in athletic populations
• Your -17.5% would be at the lower end of normal for athletes
• Must exclude pathology (myocarditis, cardiomyopathy) if symptomatic or if other abnormalities present

In acute settings 2:

• GLS <-16% indicates mild depression in acute heart failure
• Values are not applicable to patients on inotropic support or mechanical circulatory support
• Helps differentiate HFpEF from other causes of dyspnea

Follow-Up Strategy

Recommended surveillance 6:

• Repeat echocardiography with GLS in 3-6 months to establish trajectory
• Earlier repeat (4-6 weeks) if:
  • Ongoing cardiotoxic therapy exposure
  • New or worsening symptoms
  • Elevated cardiac biomarkers
• Maintain same imaging modality and vendor for serial comparisons
• Document clinical context at each measurement (medications, blood pressure, heart rate)