EXERCISE STRESS TESTING

Question 1

What is the purpose of exercise stress testing (EST)?

Answer 1

To diagnose myocardial ischemia, estimate prognosis, evaluate therapy outcomes, and assess cardiopulmonary reserve

EST uses exercise as physiological stress to detect cardiac abnormalities not present at rest.

Question 2

What methods can patients use to exercise during stress testing?

Answer 2

Treadmill, bicycle ergometer, or arm ergometer

Treadmills are more commonly used in the U.S. for EST.

Question 3

What is the difference between maximal and submaximal exercise stress tests?

Answer 3

• Maximal EST aims for the highest exercise workload tolerated by the patient
• Submaximal EST has lower targets, often used after myocardial infarction

Maximal EST is terminated based on symptoms or abnormal responses.

Question 4

What is the mean sensitivity and specificity of exercise stress testing for coronary artery disease?

Answer 4

Mean sensitivity is 68% and mean specificity is 77%

Sensitivity increases for multivessel disease and left main disease.

Question 5

What are the risks associated with exercise stress testing?

Answer 5

Morbidity less than 0.05% and mortality less than 0.01% in the general population

Slightly increased mortality and morbidity observed in patients post-myocardial infarction.

Question 6

What are common indications for exercise stress testing?

Answer 6

• Diagnosing suspected obstructive CAD
• Risk stratification in patients with known CAD
• Evaluating patients with significant clinical status changes

Other indications include post-myocardial infarction assessments and evaluating vasospastic angina.

Question 7

Should asymptomatic patients undergo exercise stress tests?

Answer 7

Generally discouraged due to low pretest probability of CAD

Selected asymptomatic patients may be considered for EST under specific clinical circumstances.

Question 8

What parameters are monitored during an exercise stress test?

Answer 8

• Clinical response to exercise
• Hemodynamic response
• ECG changes during exercise

Monitoring includes symptoms, heart rate, and blood pressure response.

Question 9

What is an adequate heart rate to elicit an ischemic response during EST?

Answer 9

85% of the maximal predicted heart rate

Achieving only 70% reduces stress-related myocardial perfusion defects significantly.

Question 10

How is the maximal predicted heart rate calculated?

Answer 10

Maximal predicted heart rate = 220 - age

Question 11

What is the Borg scale?

Answer 11

A numeric scale of perceived exertion used during EST

Values reflect levels of work, with 14 to 16 indicating anaerobic threshold.

Question 12

What defines a metabolic equivalent (MET)?

Answer 12

Caloric consumption compared to resting metabolic rate; 1 MET = 1 kilocalorie per kg per hour

Activities of 2 to 4 METs are considered light.

Question 13

What is considered a hypertensive response to exercise?

Answer 13

Systolic BP > 250 mm Hg or diastolic BP > 115 mm Hg

This response is a relative indication to terminate EST.

Question 14

Can exercise stress tests be ordered for patients taking beta-blockers?

Answer 14

Yes, but diagnostic value may be reduced due to inadequate heart rate response

Stopping beta-blockers before EST is discouraged.

Question 15

What baseline ECG findings interfere with EST interpretation?

Answer 15

• Left bundle branch block
• Ventricular pacing
• > 1-mm baseline ST depression

These conditions may require alternative diagnostic modalities.

Question 16

When can an exercise stress test be performed after an acute myocardial infarction?

Answer 16

Submaximal EST may be performed as early as 4 days after MI

Later symptom-limited tests can be conducted 3-6 weeks after the event.

Question 17

How do sex and age affect exercise stress testing results?

Answer 17

• Women have more false-positive results than men
• Age is not a significant factor if the patient can complete the exercise protocol

Both factors should be considered in the context of diagnostic accuracy.

Question 18

What are robust predictors of cardiovascular events?

Answer 18

Independent of the ECG findings

These predictors help in assessing the risk of cardiovascular events in patients.

Question 19

What diagnostic modalities should be considered for women with abnormal baseline ECG or poor exercise tolerance?

Answer 19

Coronary CTA, nuclear imaging, echocardiography pharmacological stress test

These modalities can provide additional information beyond standard exercise stress testing.

Question 20

What was the outcome of the randomized study comparing EST alone with EST with imaging?

Answer 20

No difference in cardiovascular events after 2 years and 48% cost savings compared with imaging EST

This indicates that exercise stress testing alone may be sufficient in certain cases.

Question 21

Is age an important consideration for exercise stress testing (EST)?

Answer 21

No, if the patient is fit to complete an exercise protocol adequately

Fitness level is more critical than age in determining the appropriateness of EST.

Question 22

When is an exercise stress test interpreted as positive?

Answer 22

ECG changes of ≥1 mm ST-segment depression or elevation at least 60 to 80 milliseconds after the end of the QRS complex

Also, the occurrence of angina and abnormalities in exercise capacity are considered.

Question 23

What are the absolute indications to terminate an exercise stress test?

Answer 23

• Drop of more than 10 mm Hg in systolic blood pressure
• ST elevation of more than 1 mm
• Moderate to severe angina
• Neurological symptoms
• Signs of poor tissue perfusion
• Sustained ventricular tachycardia
• Patient request to stop the test

These criteria are based on ACC/AHA guidelines.

Question 24

What is a cardiopulmonary exercise stress test?

Answer 24

A test monitoring ventilatory gas exchange during exercise to differentiate cardiac versus pulmonary causes of dyspnea

It is also used for follow-up in heart failure or transplant candidates.

Question 25

Can the ECG during exercise stress testing localize which coronary artery is affected?

Answer 25

No, exercise-induced ST depression is nonspecific; ST elevation can localize ischemia

This distinction is crucial for understanding the nature of ischemia.

Question 26

What can be done if a patient cannot exercise for a stress test?

Answer 26

Pharmacologic methods can be used with imaging modalities

These methods may include echocardiography or nuclear perfusion imaging.

Question 27

How often should a stress test be repeated?

Answer 27

When a significant change in cardiovascular status is suspected or according to specific indications

Repeating without specific clinical indication is discouraged.

Question 28

Is the 12-lead ECG obtained during an exercise stress test the same as a regular 12-lead ECG?

Answer 28

No, the Mason-Likar modification is used to avoid motion during exercise

This alteration affects the interpretation of the ECG.

Question 29

What is the Duke treadmill score?

Answer 29

A validated ECG treadmill score estimating prognosis after EST using three exercise-derived parameters

It helps identify patients at moderate to high risk for further evaluation.

Question 30

How can one estimate the pretest probability of coronary artery disease?

Answer 30

Using the Diamond and Forrester model or the Duke clinical score

These models help select the best diagnostic modality for patients.

Question 31

Fill in the blank: The Duke treadmill score includes the angina index, exercise duration, and _______.

Answer 31

ST deviation (mm)

This score helps assess the risk of coronary artery disease.