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- 4Risk Indicators from Nuclear Stress Imaging
- defect number (irreversible & reversible)
- severity of hypoperfusion (mild to severe)
- elevated lung/heart thallium uptake ratio
- left ventricular dilation induced by exercise .
- Dyspnea: at rest, with exertion, nocturnal, orthopnea, associated with angina
- Cardiac Function Tests:
- Identification of ventricular dyskinesia, akinesis, hypokinesis, aneurysms)
- Left ventricular end-diastolic pressures > 15 mm Hg
- Ejection fraction < 0.5
- Cardiac index < 2.5 liters/minute/meter2
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- Electrocardiogram:
- Arrhythmia-associated hemodynamic changes
- Indications of ischemia/infarction
- ST segmental depression
- Acute:
- may be associated with ischemia, non-Q wave infarction; hyperventilation, osmolality/electrolyte anomalies and drugs
- ECG: obtain in patients with chest pain of unknown/uncertain etiology sense acute ST segmental shift may confirm ischemia {the amount of ST depression is measured from the PR segment (isoelectric line)}
- Chronic:
- Non-specific cardiac disease marker -- associated with poor outcome
- Causes: electrolyte abnormalities; drugs (e.g. digoxin (Lanoxin, Lanoxicaps)/digitoxin (Crystodigin))
- Anatomical correlation: subendocardial damage [note that Q waves may be more likely associate with transmural infarction damage]
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Shaded areas indicate ECG changes associated was myocardial ischemia (possibly exercise into his, in this case associate with angina), adapted from the NIH publication No. 92-2890, U.S. Department of Health and Human Services, Public Health Service, National Institutes of Health, National Heart, long,and Blood Institute, April, 1994.
3D CT-based reconstructions of coronary arteries-courtesy
GE Medical Systems (http://www.crd.ge.com/esl/cgsp/projects/medical)Ventricular Functional Evaluation
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Left Image: diastole, A 6 French catheter is see in in the left ventricle (image was obtained at the end of diastole with maximal ventricular size and relaxation) -- Right Image: systole-- minimal left ventricular size following ejection
attribution:(Cardiovascular Research Institute of Southern California, Ronald P. Karlsberg, M.D., Clinical and Interventional Cardiology, Associate Clinical Professor of Medicine, UCLA School of Medicine, used with permission (http://www.cvmg.com/cvri/index.html) )
Ventriculography: Cardiovascular
Research Institute of Southern California, Ronald P. Karlsberg,
M.D., Clinical and Interventional Cardiology, Associate Clinical
Professor of Medicine, UCLA School of Medicine, used with permission
(http://www.cvmg.com/cvri/index.html) | Good Ventricular Function | Poor Ventricular Function |
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Ventricular dysfunction may be indicated by some ventricular function measures but not others.
In this case focus should be placed on the unfavorable hemodynamic parameter come e.g. LVEDP of 20 mm Hg may suggest ventricular abnormality despite a normal cardiac output
5Ejection fraction-good indicator of myocardial function and surgical outcome (population: patients undergoing coronary artery bypass grafting procedures)
Ejection fraction > 0.4: best outcome i.e. Lowest mortality, morbidity, cost
Ejection fraction < 0.3: worse outcome
Ejection fraction between 0.3 & 0.39: intermediate outcome
Low ejection fraction, < 0.4 = significant ventricular dysfunction
Ventricular dyskinesias: = significant ventricular dysfunction
Anterior wall myocardial dyskinesis/akinesis: more serious than similar findings associated with the inferior wall
Cardiac output may be normal even with low ejection fraction & dyskinetic regions in the presence of left ventricular aneurysm {ejection fraction is low due to systolic aneurysm region enlargement, but with sufficient remaining healthy myocardium, a normal cardiac output may be measured}
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Diastolic phase superimposed on the systolic phase for ejection fraction calculation (percentage of blood volume that leaves the heart/beat); Cardiac regions with previous injury, i.e. scar tissue, are associated with impaired contractility (hypokinesis). In the example above, the anterior apical region exhibits reduced motion secondary to previous left anterior descending vessel occlusion.
(courtesy of: Cardiovascular Research Institute of Southern California, Ronald P. Karlsberg, M.D., Clinical and Interventional Cardiology, Associate Clinical Professor of Medicine, UCLA School of Medicine, used with permission (http://www.cvmg.com/cvri/index.html) )
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