What further imaging, workup, or treatment is needed for a patient with severely abnormal Global Longitudinal Strain (GLS) indicating myocardial dysfunction?

Management of Severely Abnormal Global Longitudinal Strain Indicating Myocardial Dysfunction

A patient with severely abnormal Global Longitudinal Strain (GLS) requires comprehensive cardiac evaluation including cardiac MRI, biomarker assessment, and consideration for endomyocardial biopsy to determine the underlying etiology of myocardial dysfunction and guide appropriate treatment.

Diagnostic Workup

Immediate Imaging Studies

• Cardiac MRI (CMR): First-line advanced imaging to evaluate:
  • Myocardial fibrosis/scarring using late gadolinium enhancement
  • Detailed assessment of ventricular function and volumes
  • Tissue characterization to identify infiltrative conditions 1
  • Evaluation of pericardium, especially in patients with history of chest radiation 1

Laboratory Assessment

• Cardiac biomarkers:
  • Troponin I/T to assess for myocardial injury
  • BNP/NT-proBNP to evaluate for heart failure 1
  • Serial measurements to monitor disease progression

Additional Cardiac Testing

• Comprehensive echocardiography:

  • Detailed assessment of LV diastolic function
  • Evaluation of valvular function
  • Pulmonary artery pressure estimation 1
  • Serial GLS measurements using the same vendor equipment to ensure consistency 1

• Dobutamine stress echocardiography:

  • To assess contractile reserve
  • Particularly valuable in patients with heart transplant or suspected coronary allograft vasculopathy 1

• Consider endomyocardial biopsy:

  • Particularly in transplant recipients with suspected graft rejection
  • When infiltrative cardiomyopathy is suspected 1

Interpretation of GLS Findings

Severity Assessment

• GLS value of -8.00% indicates severe myocardial dysfunction with significantly increased risk of adverse cardiovascular outcomes 2
• Normal GLS values are typically more negative than -18% 2
• Relative reduction of GLS by >15% from baseline is considered abnormal and a marker of early LV subclinical dysfunction 1

Clinical Implications

• Severely abnormal GLS predicts:
  • Higher risk of heart failure hospitalizations
  • Increased risk of ventricular arrhythmias
  • Higher cardiovascular mortality 2, 3
  • Poor prognosis even with preserved ejection fraction 4

Treatment Approach

Heart Failure Management

• Initiate guideline-directed medical therapy based on ejection fraction status:
  • If reduced EF: ACE inhibitors/ARBs/ARNI, beta-blockers, MRAs, SGLT2 inhibitors
  • If preserved EF with abnormal GLS: Consider similar therapy as evidence suggests benefit in subclinical dysfunction 1

Etiology-Specific Treatment

• For transplant recipients:

  • Adjust immunosuppressive regimen if graft rejection is suspected
  • Consider coronary angiography to evaluate for coronary allograft vasculopathy 1

• For chemotherapy-related cardiotoxicity:

  • Consider cardioprotective medications (ACE inhibitors, beta-blockers)
  • Evaluate need for modification of chemotherapy regimen 1

• For valvular heart disease (particularly aortic stenosis):

  • Consider earlier intervention if GLS is severely abnormal despite preserved EF 1

Follow-up Protocol

• Serial echocardiography with GLS measurement:

  • Every 3-6 months initially
  • Using same equipment/vendor to ensure consistency 1
  • Monitor for improvement or deterioration to guide therapy

• Repeat cardiac MRI at 6-12 months to assess for structural changes and response to therapy

Special Considerations

Pitfalls in GLS Assessment

• Technical considerations:
  • Vendor variability exists - use same equipment for serial measurements 1
  • Image quality affects accuracy of strain measurements
  • Loading conditions and heart rate can affect GLS values 2

Prognostic Value

• GLS provides superior prognostic information compared to ejection fraction alone, particularly in:
  • Heart failure with preserved ejection fraction
  • Subclinical myocardial dysfunction
  • Post-transplant monitoring 1, 3, 4

Risk Stratification

• The combination of abnormal GLS and other markers (such as abnormal myocardial flow reserve) is associated with higher rates of heart failure hospitalization compared to normal GLS 3
• 3D GLS may provide better risk stratification than 2D measurements in patients with mildly-to-moderately reduced ejection fraction 4

By implementing this comprehensive approach to evaluation and management, you can identify the underlying cause of myocardial dysfunction, initiate appropriate therapy, and potentially improve outcomes in patients with severely abnormal GLS.