CCT Exercise Stress Testing 2 — Questions and Answers

Question 1: What is the most important absolute contraindication to exercise stress testing?

Acute myocardial infarction within the previous 2 days (Correct answer)
Controlled hypertension with resting BP of 150/90
Mild aortic stenosis
History of stable angina

Correct answer: Acute myocardial infarction within the previous 2 days

Acute myocardial infarction within 2 days is an absolute contraindication because exercise increases myocardial oxygen demand and can extend the area of infarction or precipitate ventricular arrhythmias in the setting of acute ischemia.

According to AHA/ACC guidelines, absolute contraindications for exercise stress testing include: acute MI within 2 days, unstable angina not yet stabilized, uncontrolled cardiac arrhythmias causing symptoms or hemodynamic compromise, symptomatic severe aortic stenosis, uncontrolled symptomatic heart failure, acute pulmonary embolism or pulmonary infarction, acute myocarditis or pericarditis, acute aortic dissection, and inability to give informed consent. Relative contraindications include less severe versions of these conditions. The distinction is critical because performing a stress test on someone with an absolute contraindication can be immediately life-threatening.

Question 2: During the Bruce protocol, a patient achieves 85% of their age-predicted maximum heart rate without symptoms or ECG changes. How is this test best interpreted?

The test is diagnostic — the patient achieved target heart rate without evidence of ischemia (Correct answer)
The test is non-diagnostic because the patient did not develop symptoms
The test should be repeated immediately at a higher workload
The test is positive for ischemia because of the high heart rate achieved

Correct answer: The test is diagnostic — the patient achieved target heart rate without evidence of ischemia

Achieving 85% or more of the age-predicted maximum heart rate (APMHR) without developing symptoms or significant ECG changes constitutes an adequate and negative stress test, providing diagnostic certainty.

A maximal (or near-maximal) stress test reaching ≥85% of APMHR (220 - age) with no ST changes, symptoms, or hemodynamic abnormalities is considered a negative/normal study that has good sensitivity for excluding significant coronary artery disease. A test terminated before this threshold without provokable findings is 'non-diagnostic' or 'submaximal' — it does not rule out significant ischemia because the heart was not challenged enough. APMHR provides a standardized endpoint since true maximum heart rate is difficult to determine.

Question 3: A patient develops 3 mm of horizontal ST depression in lead V5 at peak exercise. What does this finding indicate?

A positive stress test result suggesting myocardial ischemia (Correct answer)
A normal physiologic response to exercise
Artifact caused by lead movement during exercise
Pericarditis unmasked by exercise

Correct answer: A positive stress test result suggesting myocardial ischemia

Horizontal or downsloping ST depression of 1 mm or more (measured 60-80 ms after the J point) is the diagnostic criterion for a positive stress test indicating myocardial ischemia. 3 mm is a strongly positive finding.

The standard criterion for a positive exercise stress test is ≥1 mm of new horizontal or downsloping ST depression (measured at the J point or 60-80 ms after) in at least two contiguous leads. The magnitude of ST depression correlates with the severity of ischemia — 3 mm depression is a markedly positive result suggesting significant multi-vessel disease. ST elevation during stress testing (outside Q-wave leads) is even more concerning, indicating transmural ischemia or vasospasm. Upsloping ST depression is less specific but still warrants evaluation if ≥1.5-2 mm.

Question 4: Which finding during exercise stress testing is an indication for immediate test termination?

A drop in systolic blood pressure of more than 10 mmHg below resting baseline despite increasing workload (Correct answer)
A normal increase in heart rate from 70 to 120 bpm
Mild dyspnea that the patient tolerates
Sinus tachycardia at peak exercise

Correct answer: A drop in systolic blood pressure of more than 10 mmHg below resting baseline despite increasing workload

A drop in systolic blood pressure of more than 10 mmHg below the pre-exercise resting level during increasing workload (exertional hypotension) is an absolute indication for test termination because it suggests severe left ventricular dysfunction or outflow obstruction.

During exercise, systolic blood pressure normally rises progressively. A drop in SBP of >10 mmHg from the resting baseline (not just a failure to rise) during increasing workload is a serious finding indicating that the left ventricle cannot increase output to meet demand. This suggests severe multi-vessel CAD, left main disease, cardiomyopathy, or critical aortic stenosis. Other absolute stopping criteria include: sustained VT, ST elevation ≥2 mm in non-Q leads, patient requesting stop, signs of poor perfusion (pallor, cyanosis, confusion), inability to monitor ECG, and technical equipment failure.

Question 5: What is the purpose of the recovery phase after a stress test?

To monitor for delayed ECG changes and hemodynamic recovery, and ensure patient safety (Correct answer)
To rest the patient before they leave
To re-establish electrode contact that was lost during exercise
To recalibrate the ECG machine

Correct answer: To monitor for delayed ECG changes and hemodynamic recovery, and ensure patient safety

The recovery phase is a critical monitoring period where delayed ST changes or arrhythmias may appear, and where hemodynamic parameters (heart rate, blood pressure) return to baseline, confirming the patient is stable to leave.

The recovery phase (typically 5-10 minutes of monitored rest or slow walking) is diagnostically and clinically important for several reasons: (1) Ischemic ST changes often persist or worsen in the first 1-3 minutes of recovery; (2) Reperfusion-type arrhythmias may occur as the heart restores perfusion; (3) Failure of heart rate to decrease appropriately (heart rate recovery) is an independent prognostic marker; (4) Persistent hypotension in recovery indicates severe LV dysfunction. The patient should not be left unmonitored until heart rate and BP have returned to near-baseline levels.

Question 6: A 55-year-old patient cannot exercise on a treadmill due to severe arthritis. What is the most appropriate alternative to exercise stress testing?

Pharmacologic stress testing with vasodilators (adenosine/regadenoson) or dobutamine combined with imaging (Correct answer)
No stress testing should be performed since exercise is not possible
Rest ECG alone to evaluate for ischemia
The patient should be referred directly for coronary angiography without stress testing

Correct answer: Pharmacologic stress testing with vasodilators (adenosine/regadenoson) or dobutamine combined with imaging

Pharmacologic stress testing using vasodilators (adenosine, dipyridamole, regadenoson) or inotropic agents (dobutamine) combined with nuclear imaging or echocardiography is the established alternative for patients unable to exercise.

When patients cannot exercise adequately (orthopedic limitations, severe deconditioning, peripheral vascular disease, neurological disease), pharmacologic stress testing provides equivalent diagnostic information. Vasodilators (adenosine, regadenoson, dipyridamole) create coronary steal by maximally dilating normal vessels, revealing relative hypoperfusion in territories fed by stenotic arteries. Dobutamine (an inotrope/chronotrope) increases heart rate and contractility to mimic exercise demands. Both types are combined with nuclear imaging (myocardial perfusion imaging) or stress echocardiography for optimal sensitivity and specificity.

CCT Exercise Stress Testing 2

What is the most important absolute contraindication to exercise stress testing?