CCI Cardiac Stress Testing Protocols 2 — Questions and Answers
Question 1: Which pharmacological agent used in stress testing works by causing coronary vasodilation through A2A adenosine receptor agonism?
- Dobutamine
- Regadenoson (Correct answer)
- Atropine
- Metoprolol
Correct answer: Regadenoson
Regadenoson is a selective A2A adenosine receptor agonist that causes coronary vasodilation and is used as a pharmacological stress agent.
Question 2: A patient undergoing a dobutamine stress test develops a sustained ventricular tachycardia at 40 mcg/kg/min. What is the correct immediate action?
- Increase infusion to maximum dose
- Administer atropine 0.5 mg IV
- Stop the dobutamine infusion immediately (Correct answer)
- Continue monitoring and document finding
Correct answer: Stop the dobutamine infusion immediately
Sustained ventricular tachycardia is an absolute indication to immediately terminate the dobutamine infusion.
Question 3: During a Bruce protocol treadmill test, a patient achieves 85% of maximum predicted heart rate without symptoms or ECG changes. How should this test be classified?
- Non-diagnostic — must repeat with pharmacological stress
- Diagnostic — adequate heart rate achieved (Correct answer)
- Indeterminate — requires imaging adjunct
- Submaximal — additional workload stages required
Correct answer: Diagnostic — adequate heart rate achieved
Achieving ≥85% of maximum predicted heart rate (220 minus age) constitutes an adequate stress response, making the test diagnostically valid.
Question 4: Which finding during stress testing is considered a high-risk marker associated with severe three-vessel or left main coronary artery disease?
- ST depression confined to leads V5-V6 only
- Exercise-induced ST elevation in aVR with widespread ST depression (Correct answer)
- Isolated ST depression at peak exercise resolving within 1 minute
- Sinus tachycardia with rate-related bundle branch block
Correct answer: Exercise-induced ST elevation in aVR with widespread ST depression
ST elevation in aVR with widespread ST depression suggests diffuse subendocardial ischemia, indicating left main or proximal LAD disease.
Question 5: What is the primary reason dipyridamole is contraindicated in patients with active bronchospasm or severe reactive airway disease?
- It directly causes coronary vasospasm in these patients
- It potentiates adenosine, which can cause severe bronchospasm (Correct answer)
- It reduces heart rate too drastically during stress
- It causes systemic hypertension in bronchospastic patients
Correct answer: It potentiates adenosine, which can cause severe bronchospasm
Dipyridamole blocks adenosine reuptake, raising adenosine levels; adenosine stimulates A2B receptors causing bronchospasm in susceptible patients.
Question 6: A technologist notes that a patient scheduled for a pharmacological stress test consumed a large amount of caffeine before the study. What is the most appropriate action?
- Proceed with dobutamine stress as planned since caffeine does not affect it
- Reschedule the test, as caffeine blocks adenosine receptors and will attenuate vasodilatory stress (Correct answer)
- Administer aminophylline to counteract the caffeine effect before proceeding
- Switch to a lower dose of regadenoson to compensate
Correct answer: Reschedule the test, as caffeine blocks adenosine receptors and will attenuate vasodilatory stress
Caffeine is a competitive adenosine receptor antagonist that blunts the vasodilatory effect of adenosine-based agents, invalidating the test.
Question 7: During exercise stress testing, which blood pressure response is considered abnormal and associated with increased cardiovascular risk?
- Systolic BP rise of 40 mmHg at peak exercise
- Failure of systolic BP to rise above 10 mmHg from rest during maximal exercise (Correct answer)
- Diastolic BP increase of 10 mmHg during exercise
- Systolic BP of 180 mmHg at peak exercise in a hypertensive patient
Correct answer: Failure of systolic BP to rise above 10 mmHg from rest during maximal exercise
Exertional hypotension or a flat BP response (rise <10 mmHg) suggests severe LV dysfunction or significant left main/proximal multi-vessel disease.
CCI Cardiac Stress Testing Protocols 2
Which pharmacological agent used in stress testing works by causing coronary vasodilation through A2A adenosine receptor agonism?