Heart Viability Test: What Is It and Why Is It Important?

Introduction

The term heart viability test refers to a set of diagnostic procedures used to determine whether a portion of the heart muscle (myocardium) that appears weak or dysfunctional is still alive and can potentially recover function. This evaluation is particularly important in patients with coronary artery disease (CAD) and heart failure.

Why Is Heart Viability Important?

When the coronary arteries supplying blood to the heart become narrowed or blocked, parts of the heart muscle may receive less oxygen. This can lead to myocardial ischemia (a lack of oxygen) and potentially myocardial infarction (heart attack). However, some areas of the heart muscle may remain hibernating or stunned, meaning they are still alive but function poorly. Identifying these areas helps physicians decide whether a patient could benefit from revascularization, such as bypass surgery or stenting.

Common Tests to Assess Myocardial Viability

Several diagnostic tests assess whether heart muscle tissue is viable:

1. Cardiac MRI (Magnetic Resonance Imaging) with Late Gadolinium Enhancement (LGE)

   • Detects scarred versus viable myocardium by analyzing contrast distribution.
   • Helps differentiate between irreversible damage and salvageable tissue.

2. Dobutamine Stress Echocardiography

   • Uses a medication called dobutamine to stimulate the heart and see if weak myocardial regions can still contract.

3. Positron Emission Tomography (PET) Scan with FDG (Fluorodeoxyglucose)

   • Identifies living heart cells by assessing their ability to use glucose.
   • Active glucose metabolism suggests the presence of viable myocardium.

4. SPECT (Single Photon Emission Computed Tomography) with Thallium-201 or Technetium-99m

   • Helps assess perfusion and the ability of heart tissue to recover function after revascularization.

Clinical Implications of Heart Viability Testing

Doctors use viability testing to determine:** - Whether a patient will benefit from coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI). - If medical therapy alone is sufficient or if revascularization is necessary. - The risk of future heart failure based on the extent of viable versus non-viable myocardium.

Conclusion

If you or a loved one has been diagnosed with coronary artery disease or heart failure, heart viability testing may help guide treatment plans. Identifying salvageable heart muscle can mean the difference between heart failure progression and potential recovery.

References to Clinical Guidelines

For further reading, the following guidelines provide evidence-based recommendations on myocardial viability assessment and revascularization decisions:

Source recommendations

1. American Heart Association (AHA) Guidelines on Coronary Artery Disease

1. https://www.ahajournals.org/doi/10.1161/CIR.0000000000001168
2. https://www.heart.org/en/health-topics/consumer-healthcare/what-is-cardiovascular-disease/coronary-artery-disease
3. https://professional.heart.org/en/science-news/2023-guideline-for-the-management-of-patients-with-chronic-coronary-disease
4. https://www.heart.org/
5. https://professional.heart.org/en/guidelines-and-statements/prevent-calculator

2. European Society of Cardiology (ESC) Guidelines on Myocardial Revascularization

1. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/ESC-EACTS-Guidelines-in-Myocardial-Revascularisation-Guidelines-for
2. https://academic.oup.com/eurheartj/article/40/2/87/5079120
3. https://pubmed.ncbi.nlm.nih.gov/30165437/
4. https://www.heartuniversity.org/guidelines/esc-eacts-guidelines-on-myocardial-revascularization-2018-the-task-force-on-myocardial-revascularization-of-the-european-society-of-cardiology-esc-and-european-association-for-cardio-thoracic-surge/
5. https://pubmed.ncbi.nlm.nih.gov/25173339/