CCI Cardiac Stress Testing Protocols 5 — Questions and Answers
Question 1: A patient is referred for stress testing with a resting heart rate of 110 bpm. What is the most appropriate initial management before proceeding?
- Proceed immediately — resting tachycardia does not affect stress test validity
- Investigate and treat the underlying cause of tachycardia before stress testing (Correct answer)
- Administer beta-blocker 30 minutes before initiating the stress protocol
- Begin the stress protocol at a reduced initial workload to limit peak heart rate
Correct answer: Investigate and treat the underlying cause of tachycardia before stress testing
Resting sinus tachycardia >100 bpm is a relative contraindication to stress testing; the cause should be identified and treated before proceeding.
Question 2: What is the significance of ST-segment elevation (not depression) appearing in leads without Q waves during an exercise stress test?
- Normal variant response to sympathetic stimulation
- Reciprocal change to ischemia in a remote territory
- Indicator of severe transmural ischemia or coronary spasm requiring immediate attention (Correct answer)
- Sign of pericarditis unrelated to obstructive coronary disease
Correct answer: Indicator of severe transmural ischemia or coronary spasm requiring immediate attention
Exercise-induced ST elevation in leads without Q waves indicates severe transmural ischemia or vasospasm and requires immediate test termination.
Question 3: Which MET level achieved on exercise stress testing is generally considered to indicate good functional capacity and a favorable prognosis?
- ≥5 METs
- ≥7 METs
- ≥10 METs (Correct answer)
- ≥12 METs
Correct answer: ≥10 METs
Achieving ≥10 METs is associated with excellent prognosis regardless of ST-segment changes, as it reflects good cardiorespiratory fitness.
Question 4: A patient on a treadmill stress test develops a new 2 mm ST depression at 7 METs that fully resolves within 2 minutes of recovery. Using the Duke Treadmill Score formula (Exercise time − 5 × ST deviation − 4 × angina index), this would place the patient in which risk category?
- High risk (score ≤ −11)
- Intermediate risk (score −10 to +4) (Correct answer)
- Low risk (score ≥ +5)
- Unable to calculate without angina index
Correct answer: Intermediate risk (score −10 to +4)
With approximately 7 minutes exercise time and 2 mm ST depression without angina: 7 − (5×2) − (4×0) = −3, which falls in the intermediate-risk range (−10 to +4).
Question 5: During a vasodilator pharmacological stress test, a patient develops complete heart block. What is the correct immediate intervention?
- Increase the adenosine infusion rate to override the block
- Administer aminophylline IV and place the patient supine (Correct answer)
- Administer atropine 1 mg IV and prepare for temporary pacing
- Continue monitoring — complete heart block with adenosine is transient and self-limited
Correct answer: Administer aminophylline IV and place the patient supine
Aminophylline reverses adenosine receptor-mediated complete heart block; the agent's short half-life also means the block typically resolves rapidly with antagonism.
Question 6: Which stress testing parameter is most predictive of cardiac mortality independent of angiographic findings?
- Peak heart rate achieved
- Exercise capacity in METs (Correct answer)
- ST segment morphology at peak exercise
- Systolic blood pressure response at peak exercise
Correct answer: Exercise capacity in METs
Exercise capacity measured in METs is one of the strongest independent predictors of cardiac and all-cause mortality across multiple studies.
Question 7: An 85-year-old patient cannot exercise adequately for treadmill testing and has a documented theophylline allergy. Which pharmacological stress agent is most appropriate?
- Adenosine — rapid half-life minimizes cumulative dose concerns
- Dipyridamole — no adenosine receptor involvement
- Dobutamine — acts via adrenergic receptors, unaffected by adenosine antagonism or theophylline allergy (Correct answer)
- Regadenoson — theophylline allergy does not preclude its use
Correct answer: Dobutamine — acts via adrenergic receptors, unaffected by adenosine antagonism or theophylline allergy
Dobutamine works through beta-adrenergic stimulation rather than adenosine receptor pathways, making it the appropriate agent when adenosine-based agents are contraindicated or when aminophylline reversal is unavailable due to allergy.
CCI Cardiac Stress Testing Protocols 5
A patient is referred for stress testing with a resting heart rate of 110 bpm.
What is the most appropriate initial management before proceeding?