Preview Extract
Chapter 39
1. Which of the following statements regarding exercise testing is accurate?
1. High specificity is the real value of exercise testing in diagnosing CAD.
2. The ability of the test to detect individuals with CAD ranges from 20% to 35%.
3. The test will be positive in 77% to 90% of individuals who do not have CAD.
4. A low pretest probability increases the chances of a positive exercise test.
Answer: High specificity is the real value of exercise testing in diagnosing CAD.
Rationale:
High specificity is the real value of exercise testing in diagnosing CAD. The ability of the test
to detect individuals with CAD (sensitivity) ranges from 50% to 75%. The test will be
negative in 77% to 90% of individuals who do not have CAD. The most important factor
affecting the results is the estimation of pretest probability; therefore, the higher the pretest
probability for CAD, the greater the chance of positive results.
2. If a test standard is valid and the criteria for discriminating a positive from a negative test
remain constant, what else will remain constant?
1. Sensitivity
2. Specificity
3. Reliability
4. Accuracy
Answer: Sensitivity
Rationale:
If the standard is a valid one, and as long as the criteria for discriminating a positive from a
negative test remain constant, sensitivity will be constant. Sensitivity describes the ability of
a test to identify clients with disease. It may be calculated by dividing the number of true
positive tests by the sum of true positives plus false negatives. Specificity is calculated by
dividing the number of true negatives in the population by the sum of true negatives plus
false positives. Thus, specificity describes the frequency with which the test is normal in
subjects who are free of disease. Reliability and accuracy are measured with different data.
3. To be useful, a positive test should substantially:
1. Increase posttest probability.
2. Decrease posttest probability.
3. Increase pretest probability.
4. Increase pretest probability.
Answer: Increase posttest probability.
Rationale:
To be useful, a positive test should substantially increase the posttest probability (likelihood
that disease is present), and a negative test should lower the posttest probability. What is not
always known is the pretest probability, which is the likelihood that disease is present in the
client before testing.
4. The nurse anticipates that which of the following noninvasive tests may be ordered for
detection of coronary artery disease (CAD) in a 50-year-old male with recent episodes of
chest pain?
1. Exercise electrocardiography
2. Stress echocardiography
3. Transesophageal electrocardiography (TEE)
4. Right heart catheterization
Answer: Exercise electrocardiography
Rationale:
During exercise electrocardiography, continuous ECG and blood pressure monitoring are
performed while the client uses a treadmill or stationary bicycle. This is the most common
noninvasive test used to evaluate individuals with suspected ischemic heart disease. Stress
echocardiography would be performed over exercise electrocardiography when study results
may be limited, such as in females and those with left ventricular hypertrophy. Both TEE and
right heart catheterization are invasive and do not evaluate for coronary artery disease.
5. A client is scheduled for an ECG single-photon emission-computed tomography (SPECT).
She asks why they are doing this test. The nurse explains that:
Select all that apply.
1. SPECT images display three views of the heart instead of on a single plane.
2. SPECT images are high resolution and have better separation of overlapping myocardial
segments, which provides more specific information about cardiac muscle function.
3. SPECT images can be correlated with the ECG to assess ventricular wall motion, which
assesses the effectiveness of the heart muscle.
4. SPECT is an accurate depiction of the electrical activity of the heart.
5. SPECT gives specific information about percent of coronary artery occlusion.
Answer: 1. SPECT images display three views of the heart instead of on a single plane.
2. SPECT images are high resolution and have better separation of overlapping myocardial
segments, which provides more specific information about cardiac muscle function.
3. SPECT images can be correlated with the ECG to assess ventricular wall motion, which
assesses the effectiveness of the heart muscle.
Rationale:
SPECT images display three views of the heart instead of on a single plane. SPECT images
are obtained with a rotating gamma camera that stops at preset angles to record images,
which results in views of the heart on three different axes instead of one plane. SPECT
images are high resolution and have better separation of overlapping myocardial segments,
which provides more specific information about cardiac muscle function. SPECT provides
high resolution and better separation of overlapping myocardial segments, which provides
more specific information about cardiac muscle function. SPECT images can be correlated
with the ECG to assess ventricular wall motion, which assesses the effectiveness of the heart
muscle. SPECT images can be used with the gating technique, which allows for more
accurate interpretation because the perfusion image can be correlated with the gated image of
ventricular contraction. SPECT is an accurate depiction of the electrical activity of the heart.
SPECT does not provide information about the electrical activity of the heart. The ECG
provides that information. SPECT gives specific information about percent of coronary artery
occlusion. Heart catheterization provides information about the percent occlusion of the
coronary arteries.
6. Which diagnostic test is most effective for measuring overall heart size?
1. Echocardiogram
2. 12-lead ECG
3. CPK-MB
4. Troponin
Answer: Echocardiogram
Rationale:
Echocardiography refers to the noninvasive assessment of the structures and function of the
heart and great vessels utilizing high-frequency (ultrasound) sound waves. The 12-lead ECG
evaluates the cardiac conduction system. CPK-MB and Troponin are laboratory blood tests
that measure the amount of acute cardiac damage when diagnosing a myocardial infarction.
7. A 65-year-old male with several risk factors for CAD is scheduled for exercise testing in 2
days. The clinic nurse calls the client at home to provide instruction prior to testing. Which of
the following statements made by the client indicates a need for further teaching?
1. “I may have a cigarette or two just before the test because I’m very nervous about the
results.”
2. “I won’t eat for at least 3 hours prior to the test.”
3. “I will walk on a treadmill and my heart and blood pressure will be monitored.”
4. “I will check with the doctor to see if I should take my heart medications but will hold my
metformin until after the test.”
Answer: “I may have a cigarette or two just before the test because I’m very nervous about
the results.”
Rationale:
Clients should be instructed not to eat or smoke for 3 hours before the testing. Because the
client indicated that he will smoke up to the time of testing, further teaching is indicated. The
client’s understanding of how the test is performed is accurate. Cardiac medications are
typically not held; however, the client should confirm this with the health care provider.
Because the client is NPO for the test, metformin should be held until the test is completed
and a diet can be resumed.
8. What type of stress test is useful for clients who do not have a normal baseline ECG, or
who have physical limitations, and therefore are not suitable candidates for a standard
exercise test?
1. Exercise myocardial perfusion imaging
2. Treadmill stress test
3. Cardiovascular stress test
4. 12-lead ECG
Answer: Exercise myocardial perfusion imaging
Rationale:
Exercise myocardial perfusion imaging (MPI) is the most common application of nuclear
imaging techniques. In clients who do not have a normal baseline ECG, or who for other
reasons such as physical limitations are not suitable candidates for a standard exercise test,
imaging techniques combined with a basic stress test improve the ability to detect significant
CAD. Treadmill testing and cardiovascular stress testing refer to the same thing, and this
testing is only used when the client has a normal baseline ECG and no physical limitations.
The 12-lead ECG provides information about the electrical activity in the heart. It is not a
stress test.
9. A client is scheduled for a transesophageal echocardiogram. The client asks why it is
necessary to do this test instead of a regular, noninvasive echocardiogram. The nurse explains
to the client that this test will assist in the diagnosis of:
1. Aortic abnormalities.
2. Myocardial infarction.
3. Pulmonary embolism.
4. Coronary artery disease.
Answer: Aortic abnormalities.
Rationale:
During TEE, the miniaturized transducer is advanced down the esophagus. Because the
esophagus passes directly behind the posterior surface of the heart, it affords excellent views
of the posterior structures of the heart and great vessels. TEE is frequently used to detect and
assess endocarditis, aortic dissection, intracardiac masses such as thrombi or tumors, valvular
pathology, and congenital disorders in both children and adults. TEE is not used to diagnose
myocardial infarctions, pulmonary embolism, or coronary artery disease.
10. The nurse reviews an ECG tracing and determines that it is not a high-quality tracing.
Which of the following factors can negatively influence an ECG tracing?
Select all that apply:
1. Client movement during recording
2. History of COPD
3. Incorrect positioning of leads
4. Morbid obesity
5. Leads in firm contact with the skin
Answer: 1. Client movement during recording
2. History of COPD
3. Incorrect positioning of leads
4. Morbid obesity
Rationale:
Client movement during recording. Factors that can negatively impact the quality of an ECG
tracing include motion artifact. History of COPD. Factors that can negatively impact the
quality of an ECG tracing include COPD. Incorrect positioning of leads. Factors that can
negatively impact the quality of an ECG tracing include incorrectly positioned leads. Morbid
obesity. Factors that can negatively impact the quality of an ECG tracing include morbid
obesity. Leads in firm contact with the skin. Leads must be properly positioned and in firm
contact with the skin to ensure accuracy of the test.
11. When diagnosing an MI on a 12-lead ECG, the nurse knows that the reciprocal leads may:
Select all that apply.
1. Reflect a mirror image of the changes or damage seen in the indicative leads.
2. Be a sign of ischemia in that area.
3. Indicate there is no ischemia in that area.
4. Reflect the same ST segment elevation seen in the indicative leads.
5. Indicate heart failure.
Answer: 1. Reflect a mirror image of the changes or damage seen in the indicative leads.
2. Be a sign of ischemia in that area.
Rationale:
Reflect a mirror image of the changes or damage seen in the indicative leads. Reciprocal
(electrically opposite) leads are distant from the injury and reflect an upside-down, mirror
image of the changes or damage seen in the indicative leads. Be a sign of ischemia in that
area. These reciprocal changes can also be a sign of ischemia in that area—it doesn’t have to
be a reciprocal change. Indicates there is no ischemia in that area. Anytime there is a ST
segment change, it indicates some level of ischemia. Reflect the same ST segment elevation
seen in the indicative leads. Reciprocal leads reflect the opposite ST segment changes as the
indicative leads. Indicate heart failure. ST segment changes are not specifically indicative of
heart failure.
12. Obtaining a 12-lead ECG before treating ST segment elevation is important because:
1. The abnormality will subside and an important diagnostic indicator is lost.
2. There is no importance; an ECG may be obtained after treatment has been initiated.
3. It determines the mortality rate for MIs.
4. It is associated with Q wave changes.
Answer: The abnormality will subside and an important diagnostic indicator is lost.
Rationale:
Once the cardiac ischemia has subsided due to treatment, the ST segment changes disappear.
Therefore, it is essential that the 12-lead ECG is obtained prior to treatment. Q wave changes
indicate necrosis and will be with the client for the remainder of his or her life. ST segment
elevation in and of itself does not determine mortality.
13. A client is scheduled for percutaneous coronary intervention in the morning. Which of the
following would warrant a call to the health care provider by the nurse?
1. Client has an order for metformin each morning.
2. Client’s serum creatinine is 1.0 mg/dL.
3. Client takes warfarin at home and current INR is 1.
4. Client’s potassium level is 3.8 mEq/L.
Answer: Client has an order for metformin each morning.
Rationale:
Metformin has been associated with an increased risk for lactic acidosis after PCI. The drug
should be held on the day of the procedure and for 48 hours after the procedure. The nurse
will need to contact the health care provider for such orders. The client’s creatinine, INR, and
potassium level are all within normal limits, so no intervention is necessary.
14. Your client with unstable angina who is going for a heart catheterization asks you why the
procedure is being done. You explain it will:
Select all that apply.
1. Provide information about structural abnormalities in the heart.
2. Diagnose plaque build-up in the coronary arteries.
3. Assist in the diagnosis of heart failure.
4. Diagnose valve disorders.
5. Assess ventricular septal defects.
Answer: 1. Provide information about structural abnormalities in the heart.
2. Diagnose plaque build-up in the coronary arteries.
3. Assist in the diagnosis of heart failure.
4. Diagnose valve disorders.
Rationale:
Provide information about structural abnormalities in the heart. Dye is injected into the heart
chambers to obtain information about chamber size and the anatomy of the great vessels,
which helps determine structural abnormalities. Diagnose plaque build-up in the coronary
arteries. The patency of coronary arteries is evaluated by injecting dye into the arteries; this
provides information about the lumen patency, which is used to evaluate the extent of
coronary artery disease. Assist in the diagnosis of heart failure. Hemodynamic pressures can
be measured and used to evaluate for heart failure and pulmonary function. Diagnose valve
disorders. Pressure gradients across valves evaluate the extent of stenosis or regurgitation.
Assess ventricular septal defects. Dye is injected into the right ventricle and images are
obtained to determine if the dye follows the normal blood flow pattern or if it goes directly
from the right ventricle to the left ventricle. The right-to-left ventricular flow pattern indicates
that there is a hole in the septum.
15. A client returns to his room following a cardiac catheterization. Which of the following
assessments, if made by the nurse, would justify calling the health care provider?
1. Absence of pulse distal to the catheter insertion site
2. Pain at the site of the catheter insertion
3. Drainage on the dressing covering the catheter insertion site
4. Redness at the catheter insertion site
Answer: Absence of pulse distal to the catheter insertion site
Rationale:
Absence of a pulse distal to the catheter insertion site indicates clot formation in the artery.
The health care provider needs to be notified so measures can be taken to remove the clot and
restore tissue perfusion. Pain, some drainage, and redness are all expected following the
insertion of a catheter.
Test Bank for Timby's Introductory Medical-Surgical Nursing
Loretta A Donnelly-Moreno, Brigitte Moseley
9781975172237, 9781975172268
