CCI Cardiac Stress Testing Protocols 3 — Questions and Answers
Question 1: Which stress testing modality is preferred for evaluating coronary artery disease in a patient with a left bundle branch block (LBBB)?
- Standard Bruce protocol treadmill ECG stress test
- Adenosine or regadenoson myocardial perfusion imaging (Correct answer)
- Dobutamine stress echocardiography
- Submaximal bicycle ergometry with ECG monitoring
Correct answer: Adenosine or regadenoson myocardial perfusion imaging
LBBB causes false-positive septal perfusion defects with exercise; vasodilator pharmacological stress (adenosine/regadenoson) with imaging avoids this artifact.
Question 2: What is the maximum infusion rate of dobutamine typically used in a standard dobutamine stress echocardiography protocol?
- 20 mcg/kg/min
- 30 mcg/kg/min
- 40 mcg/kg/min (Correct answer)
- 50 mcg/kg/min
Correct answer: 40 mcg/kg/min
The standard dobutamine stress echo protocol escalates to a maximum of 40 mcg/kg/min, with atropine added if target heart rate is not achieved.
Question 3: A patient experiences chest pain and 3 mm downsloping ST depression in leads V4-V6 at 5 METs on a treadmill test. According to Duke Treadmill Score, which risk category does this represent?
- Low risk
- Intermediate risk
- High risk (Correct answer)
- Indeterminate — insufficient data
Correct answer: High risk
A Duke Treadmill Score ≤ -11 (calculated from exercise time, ST deviation, and angina index) corresponds to high risk with significant ST depression at low workload.
Question 4: What is the reversal agent for adenosine-induced severe bronchospasm or hypotension during pharmacological stress testing?
- Atropine 0.5 mg IV
- Aminophylline 50-100 mg IV (Correct answer)
- Epinephrine 1 mg IV
- Metoprolol 5 mg IV
Correct answer: Aminophylline 50-100 mg IV
Aminophylline (theophylline) competitively antagonizes adenosine receptors and rapidly reverses adenosine-induced side effects.
Question 5: Which of the following represents an absolute contraindication to exercise stress testing?
- Stable angina pectoris with recent symptoms
- Uncontrolled symptomatic heart failure with resting dyspnea (Correct answer)
- Hypertension with BP 150/90 on medications
- Moderate mitral regurgitation with preserved LVEF
Correct answer: Uncontrolled symptomatic heart failure with resting dyspnea
Decompensated heart failure with active symptoms at rest is an absolute contraindication to exercise stress testing due to risk of acute decompensation.
Question 6: During a stress test, a patient develops 2 mm horizontal ST depression in 5 leads at peak exercise, with the changes persisting for 8 minutes into recovery. What does prolonged ST depression recovery suggest?
- Normal variant — recovery time is not clinically significant
- Benign response limited to the exercise phase only
- More extensive ischemia and higher risk of significant CAD (Correct answer)
- Vasospastic angina unrelated to obstructive disease
Correct answer: More extensive ischemia and higher risk of significant CAD
ST depression persisting beyond 5 minutes into recovery is associated with more extensive ischemia and increased likelihood of significant multi-vessel coronary disease.
Question 7: A technologist is setting up a modified Bruce protocol instead of the standard Bruce protocol. What is the key difference in a modified Bruce protocol?
- It uses lower maximum heart rate targets for all patients
- It begins with two lower-workload warm-up stages before stage 1 of the standard protocol (Correct answer)
- It adds pharmacological support at stage 3 if heart rate is inadequate
- It limits maximum exercise time to 9 minutes regardless of patient tolerance
Correct answer: It begins with two lower-workload warm-up stages before stage 1 of the standard protocol
The modified Bruce protocol adds stages 0 and 0.5 (lower speed/grade) before the standard stage 1, making it more appropriate for deconditioned or elderly patients.
CCI Cardiac Stress Testing Protocols 3
Which stress testing modality is preferred for evaluating coronary artery disease in a patient with a left bundle branch block (LBBB)?