What is the recommended approach for a stress test in patients?

Recommended Approach for Stress Testing in Patients

The recommended approach for stress testing in patients should be based on the patient's ability to exercise, ECG characteristics, and clinical presentation, with exercise stress testing being the preferred initial test for most patients who can exercise adequately and have interpretable ECGs.

Initial Test Selection

• Standard exercise ECG stress testing is the initial test of choice for patients who can exercise adequately and have a normal or near-normal resting ECG without confounding factors 1, 2
• Exercise stress testing provides valuable information on exercise capacity, symptoms, blood pressure response, and risk stratification 3, 4
• For most applications, exercise should be used as the most appropriate form of stress when possible 3

Specific Recommendations Based on Patient Characteristics

For Patients Who Can Exercise:

• With normal resting ECG and not on digoxin: Standard treadmill exercise testing is recommended 3, 1
• With abnormal resting ECG or on digoxin: Exercise imaging testing (echocardiography or myocardial perfusion imaging) is recommended 3
• With left bundle-branch block or electronically paced ventricular rhythm: Exercise testing is not recommended; pharmacologic stress imaging is preferred 3

For Patients Unable to Exercise:

• Without left bundle-branch block or paced rhythm: Pharmacologic stress with either:
  • Dipyridamole or adenosine myocardial perfusion imaging 3, 5
  • Dobutamine echocardiography 3
• With left bundle-branch block or paced rhythm: Dipyridamole or adenosine myocardial perfusion imaging is recommended 3

Exercise Protocols

• The Bruce protocol is commonly used in North America, but may not be appropriate for all patients 6
• For patients with limited exercise capacity, protocols with smaller increments in workload should be considered 6
• The test should aim to reach maximal capacity in 8-12 minutes 6

Pharmacologic Stress Testing

• Dobutamine produces stress through increased cardiac contractility and heart rate 3
• Adenosine and dipyridamole dilate normal coronary arteries to produce regional differences in perfusion 5
• Adenosine is administered at 0.14 mg/kg/min infused over six minutes (total dose of 0.84 mg/kg) 5
• Pharmacologic stress testing should be reserved for patients unable to exercise adequately 7

Special Considerations

For Cardiac Risk Assessment:

• In asymptomatic young adults (<30 years) with aortic stenosis, exercise stress testing is reasonable to determine exercise capability, symptoms, and blood pressure response 3
• For patients with suspected or known coronary artery disease, stress testing is valuable for risk stratification 1

For Diastolic Function Assessment:

• Exercise using a supine bicycle is recommended for diastolic stress echocardiography to evaluate patients with unexplained dyspnea or suspected heart failure with preserved ejection fraction 3

For Post-Acute Coronary Syndrome:

• Low and intermediate-risk patients with unstable angina, acute coronary syndromes, or chest pain should undergo exercise stress testing when clinically stable 3

Contraindications and Safety

• Stress testing should not be performed in patients with severe comorbidity likely to limit life expectancy or candidacy for revascularization 3
• Contraindications for adenosine include bronchospastic lung disease, second or third-degree AV block, and sinus node disease 5
• Personnel must be properly trained and aware of emergency procedures to ensure patient safety 6

Interpretation and Follow-up

• A normal response involves augmentation of function in all LV segments and increases in ejection fraction and cardiac output 3
• The Duke treadmill score has excellent prognostic value for exercise stress testing 2
• Normal results on a stress test are highly predictive of an excellent prognosis 3