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33 Cards in this Set
- Front
- Back
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The right coronary artery supplies? |
The SA and AV nodes, the right ventricle, and inferior wall |
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The LAD supplies? |
The interventricular septum and apex |
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The left circumflex supplies? |
the anterolateral wall |
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What are factors affecting the supply of oxygen by coronary arteries? |
-degree of obstruction -length of obstruction (longer= larger pressure drop) -dynamic properties of lesion (?) -dynamic properties of distal vascular bed (can is vasodilate?) -thickness of the myocardium -potential for collateral flow |
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What are the indicators of myocardial oxygen demand? |
-BP (systolic) x HR -contractility -wall stress as determined by Laplace's law |
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Define Laplace's law. |
Wall stress is = P(ressure) x R(adius)/ 2h (Wall thickness) |
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What are the main factors affecting myocardial oxygen supply? |
Coronary arteries: -atherosclerosis -coronary vasospasm -hypoxemia -anemia -hypotension -coronary vasculitis -coronary anomalies |
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Degree of perfusion of coronary arteries is determined by? |
diastolic blood pressure; coronary perfusion is predominant during diastole. |
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What are the different classes of angina? |
Class 1: with much exertion Class 2: with moderate exertion Class 3: minimal exertion (usually with ADLs) Class 4: at rest
angina progressing from one category to the next needs to be treated more aggresively. |
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Different types of chest discomfort? |
Cardiac Gastrointestinal Musculoskeletal Pulmonary |
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Factors for assessing CAD on PE? |
-HTN -body weight/ "habitus" -vascular bruits -heart size -skin -eye grounds- including xanthelasma (cholesterol deposits in skin around orbit), corneal arcus (deposits around iris) |
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What are two clinical signs of HTN on eye exam? |
-AV nicking - retinal hemorrhage |
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T/F A normal ECG excludes coronary artery disease. |
False. |
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When should a stress test be performed? |
when history and PE are equivocal |
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What is a MET? |
MET is a measure of calorie expenditure defined as 1 kcal/ kg body wt/ hour.
This is used to measure energy expenditure as compared to that at rest
protocols for stress test including both stepped and gradual increases in MET |
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What is the diagnostic level of stress on stress test? |
85% maximum HR (220-age)
if this is not achieved the test is considered negative, the patient is generally pushed until exhaustion |
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When is the stress test considered positive? |
When the patient's chest discomfort is reproduced or the ECG abnormalities consistent with ischemia develop ( >1mm horizontal or downsloping ST segment depressions) |
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What is the sensitivity and specificity of the stress test in a high prevalence population? |
70% in both for high prevalence population |
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What is the sensitivity and specificity of stress test in low prevalence population? |
same as in high prevalence. |
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What is the sensitivity determined by? |
the false negative and true positive rates. |
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T/F A stress test has fewer false positives and fewer false negatives than ECG test. |
True, theses are the definitions of specificity and sensitivity, respectively. |
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T/F A stress test has more true positives and more true negatives than an ECG test. |
Truth. These are the definitions of sensitivity and specificity, respectively |
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What is a pharmacologic stress test? What are the drugs used? |
when exercise stress test is unable to be given (i.e. arthritis), dobutamine (beta agonist) is given to increase heart rate and contractility (oxygen demand) in an attempt to reproduce patient's chest discomfort.
Adenosine or dipyridamole can also be given. These are vasodilators that will increase blood flow, but help to exaggerate the difference between healthy and occluded vessels. Minimal change in HR, BP or contractility. |
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On stress test, ST depression is indicative of ________. |
subendocardial ischemia |
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ST elevation of stress test is indicative of _______. |
transmural ischemia |
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What are additional indications for exercise testing? |
-adequacy of therapy (medical or revascularization) -activity counseling (MET chart) -exercise prescription -rhythm assessment -Valvular heart disease (aortic stenosis, mitral stenosis, mitral regurgitation, hypertrophic obstructive cardiomyopathy) |
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When should a stress imaging test be ordered? |
when there are baseline abnormalities in the ECG that make the exercise test less useful
ST segments Left bundle branch block LVH with strain
These studies increase sensitivity and specificity, as well as aid in localizing ischemia to a specific coronary artery
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In stress nuclear testing, how can one tell the difference between transient ischemia and an infarct? |
contrast is given and both appear as "cold spots" during exercise. When exercise stops, transient ischemic areas should fill in with contrast. |
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What is stress echo useful for? |
LV contractile function is assessed at baseline and after exercise, testing to see if contractile function develops.
also useful in patients with baseline S or T wave abnormalities |
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When is cardiac catherization indicated? |
for patients not responding well to pharmacological therapy, are unstable, and with non invasive results so abnormal that need for revascularization is likely.
"gold standard" in diagnosing CAD |
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What are the disadvantages of catheterization? |
provides only anatomic information, does not give pathophysiologic consequences.
treatment must be based on functional effects, manifested by symptoms.
invasive procedure with bleeding risks. |
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What is the most useful role of CTA (CT angiography)? |
to rule out CAD in patients with chest pain and low clinical suspicion of serious CAD. |
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What is the major advantage of CTA? |
besides noninvasive, it has a high negative predictive value (96%) |
