Review of Section 6 : Self-test
Please find the answers by scrolling to the bottom of the page.
1. What is myocardial ischemia?
2. What is the rationale in evaluating for ischemia using an exercise stress test?
3. What is the treatment for arrhythmias?
4. Explain what is meant by myocardial “stunning”
5. What happens with chronic or repeated stunning?
6. What is remodeling?
7. What does electrocardiography tell us about cardiac function?
8. What is the most important indicator of prognosis?
9. What is an “infarct-avid” isotope?
10. How does Tc99m Pyrophosphate localize in infarcted tissue?
11. What is thallous chloride’s mechanism of localization?
12. What type of photons are used for thallium imaging?
13. What are some of the factors that define an electrically “positive” stress test?
14. What characteristics of thallium allows us to perform stress and rest imaging in the same day?
15. Where does MIBG localize for adrenergic neuronal mapping?
16. What PET myocardial imaging agent is similar to Thallium-201?
ANSWERS
1. Ischemia is defined as deficiency of blood supply.
2. Exercise causes vasodilation in normal vessels, but diseased areas remain narrow. Stress flow is compared to rest flow.
3. An Electrophysiology study identifies abnormal conduction zones and ablates tissue with radio frequency, laser or cryotherapy.
4. ‘Stunned’ myocardium is viable but recovering from prolonged inadequate oxygen (blood flow). Contracile function may remain depressed for weeks.
5. ‘Stunning’ shifts chronically ischemic myocardium to anaerobic metabolism.
6. Inelastic scar tissue replaces muscle tissue and performance declines.
7. Electrocardiography cannot tell us about cardiac function.
8. Left Ventricular Ejection Fraction.
9. An isotope absorbed in or around necrotic cells.
10. Tc99m-Pyp is absorbed into hydroxyapatite crystals surrounding dead cells.
11. Thallous chloride enters cells with the Sodium-Potassium pump mechanism, being chemically similar to Potassium ions.
12. X rays from Mercury L-alpha and K-beta characteristic x-rays in the range of 69 to 83 keV. Decays by Electron Capture.
13. ST segment depression or elevation greater than 1 mm compared to a normal baseline, 2 mm or more increase in the ST-segment abnormality in patients with a baseline ST-segment depression.
14. After rapid first pass extraction post stress injection, TL201 migrates out of the cellular space and redistributes.
15. MIBG is absorbed by intact sympathetic nerve endings.
16. Rubidium-82
