What is nonviable myocardium?
Accurate identification of patients likely to benefit from interventions such as coronary revascularization requires the differentiation of viable (reversibly dysfunctional) myocardium from nonviable (persistently dysfunctional) tissue.
What does stunned myocardium mean?
Definitions: Stunned myocardium is viable myocardium salvaged by coronary reperfusion that exhibits prolonged postischemic dysfunction after reperfusion. Hibernating myocardium is ischemic myocardium supplied by a narrowed coronary artery in which ischemic cells remain viable but contraction is chronically depressed.
What is Subendocardial myocardium?
A subendocardial infarct results in necrosis exclusively inolving the innermost aspect of the myocardium. Usually a subendocardial infarct is the result of a partially occluded epicardial coronary artery (i.e. NSTEMI).
What is a viable heart?
A Nuclear Medicine Thallium Viability Scan is a test used to evaluate the blood flow to the heart. After a heart attack (myocardial infarction), some of the heart muscle may be permanently damaged or scarred. Once this occurs, the area affected will cease to function properly.
What is a hibernating myocardium?
The term “hibernating myocardium” refers to the presence of persistently impaired LV function at rest, due to a reduced coronary blood flow that can be partially or completely restored to normal after revascularization.
What is neurogenic stunned myocardium?
Neurogenic stunned myocardium may be defined as myocardial injury and dysfunction occurring after diverse types of acute brain injury as a result of imbalance of the autonomic nervous system.
What is Subendocardial infarct?
Subendocardial infarction was defined as typical chest apin (greater than 15 minutes), serum enzyme elevation and persistent (greater than 48 hours) new T wave inversion and/or S-T segment depression in the absence of new pathologic Q waves.
What is left ventricular myocardium?
The LV wall consists of three distinct layers: an inner endocardium, a middle myocardium, and an outer epicardium. The myocardium consists primarily of contractile cardiac myocytes, fibroblasts, and an abundant extracellular matrix.
What is a cardiac PET scan?
A heart positron emission tomography (PET) scan is an imaging test that uses a radioactive substance called a tracer to look for disease or poor blood flow in the heart.
Is myocardial viability an all-or-none phenomenon?
Thus myocardial viability is interpreted as an all-or-none phenomenon as SPECT cannot assess the transmural extent of variability within the left ventricular wall. The advantage of 99mTc-sestamibi is its much shorter protocol duration with rest imaging occurring approximately 1 hour after tracer administration.
Which modalities are used to assess myocardial viability in cardiac patients?
Patients with myocardial viability have increased mortality if treated medically and do not undergo revascularization. Out of the most commonly used modalities to assess viability, CMR and PET offer the highest sensitivity and specificity.
What happens if myocardial perfusion is not restored?
If myocardial perfusion is not restored, irreversible myocardial necrosis can occur. The goal of viability testing, detailed in the next section, is to determine if a large portion of dysfunctional myocardium is nonviable in which case the risks would likely outweigh benefit of revascularization. 3.
What is myocardial viability during dobutamine echocardiography?
Myocardial viability during dobutamine echocardiography predicts survival in patients with coronary artery disease and severe left ventricular systolic dysfunction. J Am Coll Cardiol. 1998;32:921–926. [PubMed] [Google Scholar] 27.