Why should patients with leukemia undergo electrocardiogram (ECG) and echocardiogram?

Cardiac Monitoring in Leukemia Patients: The Need for ECG and Echocardiography

Patients with leukemia should undergo ECG and echocardiography prior to treatment to establish baseline cardiac function and detect pre-existing abnormalities, as many chemotherapeutic agents used in leukemia treatment can cause cardiotoxicity that may lead to significant morbidity and mortality. 1

Rationale for Cardiac Monitoring in Leukemia

Risk of Cardiotoxicity

• Leukemia treatments, particularly anthracyclines, are associated with significant cardiotoxicity that can manifest during treatment or years after completion 2
• Cardiac events may include arrhythmias, myocarditis, cardiomyopathy, and heart failure, which significantly impact morbidity, mortality, and quality of life 2
• Cardiotoxicity can be acute (occurring during or shortly after treatment), subacute (within weeks), or chronic (months to years after treatment) 2, 3

Pre-Treatment Cardiac Evaluation

Electrocardiogram (ECG)

• ECG is recommended for all leukemia patients before initiating potentially cardiotoxic chemotherapy 1
• ECG helps detect pre-existing cardiac abnormalities including conduction disturbances, arrhythmias, and ST-T wave changes that may increase risk of treatment-related complications 1
• Baseline ECG provides a reference point for comparison during and after treatment to identify new-onset cardiac abnormalities 1, 2

Echocardiography

• Echocardiography is the first-line cardiac imaging technique for identifying baseline cardiac function and monitoring for cardiotoxicity 1
• The NCCN guidelines for Acute Myeloid Leukemia specifically recommend echocardiogram for patients with: 1
  • History or symptoms of cardiac disease
  • Prior or planned exposure to cardiotoxic drugs
  • History of thoracic radiation
  • Older age
• For Acute Lymphoblastic Leukemia, echocardiogram is recommended as part of the initial evaluation 1

Parameters to Evaluate

Left Ventricular Function

• Left ventricular ejection fraction (LVEF) is the primary parameter for monitoring cardiac function 1
• Normal LVEF is >52% for men and >54% for women; a drop of >10% or to <50% indicates cardiotoxicity 1, 4
• Global longitudinal strain (GLS) by speckle tracking echocardiography is more sensitive than LVEF for early detection of subclinical myocardial dysfunction 1, 4
• A GLS reduction >15% from baseline is considered abnormal and may predict future cardiac dysfunction even when LVEF remains normal 1

Other Echocardiographic Parameters

• Assessment of left ventricular mass indexed by body surface area, which may increase with certain treatments 1
• Evaluation of diastolic function, as some chemotherapeutic agents can cause diastolic dysfunction before systolic impairment 5
• Assessment of valvular function, particularly in patients who will receive or have received radiation therapy 1, 3

Timing of Cardiac Monitoring

Baseline Assessment

• ECG and echocardiography should be performed before initiating chemotherapy to establish baseline cardiac function 1
• In acutely ill patients, treatment should not be delayed for an echocardiogram 1

During Treatment

• Serial monitoring with ECG and echocardiography is recommended during treatment, particularly after cycles of anthracycline-based chemotherapy 5, 4
• Monitoring frequency should be based on the specific chemotherapy regimen, cumulative dose, and individual risk factors 1, 2

Post-Treatment

• Continued cardiac surveillance is recommended after completion of therapy, as cardiotoxicity may develop months or years after treatment 1, 2
• Most cases of treatment-associated cardiac dysfunction develop within the first year after completion of therapy 1, 3

Special Considerations

Advanced Imaging Techniques

• Three-dimensional echocardiography provides better reproducibility for LVEF measurement than standard 2D echocardiography 1, 3
• Cardiac MRI may be considered when echocardiography is suboptimal or to confirm LVEF <53% 1
• Multigated angiography (MUGA) provides reproducible LVEF measurements but involves radiation exposure and should be considered only when echocardiography and cardiac MRI are unavailable 1

Biomarkers

• Cardiac biomarkers (troponins, BNP, NT-proBNP) may complement imaging for early detection of cardiotoxicity 1, 5
• Elevated NT-proBNP levels after chemotherapy may indicate subclinical cardiotoxicity even before echocardiographic changes 5

Prevention and Management of Cardiotoxicity

• Early detection of cardiotoxicity allows for timely intervention with cardioprotective medications 1, 2
• Beta-blockers and ACE inhibitors may prevent or mitigate chemotherapy-induced cardiotoxicity 1
• Modification of chemotherapy regimens may be necessary if significant cardiotoxicity is detected 2

By implementing comprehensive cardiac monitoring with ECG and echocardiography, clinicians can identify patients at risk for cardiotoxicity, detect early cardiac dysfunction, and intervene appropriately to reduce morbidity and mortality in leukemia patients undergoing treatment.