Cardiac Laboratory and Diagnostics (Exam 2)

Question 1

Describe lipid profiles and the indications for use.

Answer 1

Men 35 or older and women 45 or older (not recommended in those older than age 75.

Question 2

Describe what a resting EKG is and the indications for use.

Answer 2

It is most important initial test for ischemic heart disease. Classic findings: reversible ischemia (angina): ST depression, T-Wave flattening/inversion.
Acute MI: ST elevation followed by Q waves. A completely normal EKG doesn’t exclude angina or acute MI.

Question 3

What is the indication for use of a stress EKG?

Answer 3

evaluate for angina/ischemia-used to induce myocardial ischemia when not present at rest. Patients with suggestive symptoms, high-risk patients (hyperlipidemia, DM), patients with strong family history of early CAD, older patients beginning strenuous activity program. Often combined with radionuclide or echo.

Question 4

Describe a stress EKG.

Answer 4

Exercise on treadmill or stationary bike
various protocols (most common is “Bruce”
Positive test: ST depression >/= 1 mm
Positive test usually followed by coronary angiogram.

Question 5

Describe a chest X-ray and indications for use.

Answer 5

Often normal in patients with ischemic heart disease.
Assess for:
heart size (cardiomegaly)
lung fields for interstitial edema (sign of CHF)
Indicated for those with chest pain or shortness of breath.

Question 6

What is the indication for use of cardiac enzyme tests?

Answer 6

Enzyme rise indicates irreversible myocardial cell damage. Normal serial enzymes rule out acute MI, but do not rule out coronary artery disease-chest pain may still be due to unstable angina. Peak level of enzymes correlate with amount of myocardial damage.

Question 7

Describe a cardiac enzyme test.

Answer 7

Myoglobin: very sensitive, not specific. early rise: 1-2 hours. Peak: 4-6 hours. Normalize 1 day.
Troponin: still quite sensitive and very specific for MI. early rise: 3-6 hours. Peak: 12-24 hours. Normalize: 7 days.

Question 8

What is the indication for use of Brain Natriuretic Peptide (BNP) testing?

Answer 8

Helps distinguish CHF from other causes of dyspnea.

Question 9

Describe a BNP test.

Answer 9

A polypeptide secreted by cardiac ventricles in response to increased ventricular volume/pressure-rises in CHF

Question 10

Describe Stress radionuclide studies and when they are used.

Answer 10

Used to detect coronary artery disease, reversible ischemia, or old/recent MI. A radionuclide is injected during exercise. A zone of hypoperfusion may indicate reversible ischemia or scar. If reversible, perfusion defects will fill in during rest period. If old, perfusion defects persist despite rest.

Question 11

What are the indications for use of a multiple-gated blood pool imaging (MUGA scan)?

Answer 11

calculate left ventricular ejection fraction-patients getting chemo may get scan to make sure no cardio side effects from chemo. Look for focal wall motion abnormality after MI. Look for temporary wall motion abnormality with exercise (reversible ischemia).

Question 12

Describe a MUGA scan.

Answer 12

Red blood cells are labeled with technetium-99. The heart is imaged through several hundred cardiac cycles to provide clear image of the heart throughout the cycle.

Question 13

What are the uses of a PET scan?

Answer 13

Distinguishes stunned myocardium from scar by showing persistent metabolism in areas of reduced blood flow.

Question 14

Describe a PET scan.

Answer 14

Uses positron emitting agents to show perfusion/glycolytic metabolism of myocardium.

Question 15

How does echocardiography work?

Answer 15

Demonstrates chamber size, function, thickness-left ventricular ejection fraction (important prognostic indicator). segmental “wall motion abnormalities”

Question 16

How is echocardiography used?

Answer 16

wall abnormalities indicate ischemia or prior MI. Identifies pericardial effusions.

Question 17

What is a two-dimensional echocardiogram?

Answer 17

cross-section of cardiac structures

Question 18

What is a color-flow doppler?

Answer 18

measures speed and direction of cardiac blood flow. detects valvular regurgitation

Question 19

What is a transesophageal echo (TEE)?

Answer 19

Transducer passed into esophagus. enables clearer visualization of cardiac structures-can be useful for detecting vegitations of the heart valves or blood clots forming on the valves.

Question 20

Describe a stress echo and when it should be used.

Answer 20

Performed at rest and with exercise.
wall motion abnormalities indicate either reversible ischemia or prior infarction.
Reversible ischemia: produces exercise-induced wall motion abnormalities (defects are present only with exercise).
Prior MI: “fixed defect” that is present with both rest and exercise.

Question 21

What do you do if a person can’t do a stress test because of their inability to do the physical work?

Answer 21

Pharmacologic induced stress: adenosine

Question 22

Describe a coronary CT angiogram (CCTA).

Answer 22

Noninvasive method to image coronary arteries. Downside is radiation. If the test is negative there is certainty that there is no issues. Sensitivity: 95% Specificity 60-90%-may look more occluded than it actually is.

Question 23

What are the indications for use of a CCTA?

Answer 23

Symptomatic patients at intermediate risk for CAD.

Equivocal/nondiagnostic stress test.

Question 24

What is a cardiac MRI used for?

Answer 24

Usually research but being investigated fo possible use of imaging coronary arteries for CAD.

Question 25

Describe a cardiac MRI.

Answer 25

Provides excellent anatomic definition of heart
-myocardial thickness
-chamber size
-many congenital defects
Rapid sequence MRI shows LV function and wall motion (useful if echo is suboptimal)

Question 26

What are the indications for use of Cardiac Catheterization?

Answer 26

patients being considered for angioplasty/stent or coronary artery bypass grafting (CABG) because of:

• anginal symptoms not responding to medication
• unstable angina
• non-invasive tests demonstrate high-risk disease
• recurrent symptoms in pt with prior angioplasty or CABG
• Pts surviving sudden death from life-threatening arrhythmiain which CAD may be the cause
• chest pain or cardiomyopathy of unknown cause
• acute MI in ER

Question 27

Describe a cardiac catheterization.

Answer 27

Gold standard-the definitive diagnostic test for CAD. Selective catheterization of coronary arteries followed by injection of contrast. Visualizes location and severity of coronary artery stenosis. Angioplasty/stenting can be performed as part of same procedure.

Question 28

Why is cardiac catheterization not typically first line for diagnostic testing?

Answer 28

Really expensive and invasive.

Question 29

What is a holter monitor?

Answer 29

portable cardiac monitor worn by pt to record cardiac activity for 24-48 hours.

Question 30

what is an event monitor?

Answer 30

records only when patient activates it (when patient is experiencing symptoms). preferable when symptoms are infrequent and might not be caught in a 24 hour period.

Question 31

What is ambulatory EKG monitoring used for?

Answer 31

useful in diagnosis of arrhythmias: symptoms are often not present at time of office/hospital evaluation. can demonstrate the arrhythmia present at the time the symptoms occur.