What is a Graded Stress Test
A graded stress test is a cardiovascular diagnostic procedure involving continuous ECG monitoring and blood pressure measurements during progressively increasing exercise intensity (typically on a treadmill or cycle ergometer) until reaching predetermined endpoints, used to evaluate cardiac function and detect coronary artery disease. 1
Definition and Procedure
A graded stress test consists of the following core components:
- Continuous ECG monitoring using either 3-lead or 12-lead systems with frequent 12-lead recordings taken according to clinical circumstances 1
- Progressive exercise intensity that increases in stages, most commonly using a treadmill or cycle ergometer 1
- Frequent blood pressure determinations made before, during, and after exercise 1
- Exercise to specific endpoints which may include target heart rate, symptoms, ECG changes, or blood pressure responses 1
The test may be combined with additional imaging modalities such as myocardial perfusion imaging, radionuclide ventriculography, echocardiography, magnetic resonance imaging, or metabolic measurements 1
Who Orders and Performs the Test
Ordering Physicians
The test is typically ordered by physicians evaluating patients for:
- Suspected or known coronary artery disease with chest pain or other cardiac symptoms 2, 3
- Preoperative risk assessment for patients with poor functional capacity (<4 METs) and elevated cardiovascular risk 2
- Asymptomatic high-risk patients including diabetics ≥40 years planning vigorous exercise 2
Personnel Who Perform the Test
The test can be safely supervised by properly trained non-physicians including nurses, physician assistants, exercise physiologists, physical therapists, or medical technicians working under direct physician supervision 1. The supervising physician should be in the immediate vicinity, on the premises, or available for emergencies 1
Direct physician presence is required when testing patients with:
- Recent (within 7-10 days) documented acute coronary syndrome 1
- Severe left ventricular dysfunction 1
- Severe valvular stenosis (e.g., aortic stenosis) 1
- Complex arrhythmias 1
Non-physician supervisors should have specific cognitive skills and may be certified by organizations such as the American College of Sports Medicine 1
Test Interpretation
A qualified physician must interpret the test results, which requires understanding:
- Indications and contraindications for testing 1
- Normal endpoints and abnormal responses requiring test discontinuation 1
- Management of test complications 1
- Factors causing false-positive, false-negative, or indeterminate results 1
- How positive and negative predictive values vary according to disease prevalence (Bayes' theorem) 1
Important Safety Considerations
The test carries a small but definite risk, with up to 1 myocardial infarction or death per 2,500 tests 1. Therefore, it should only be performed with:
- Appropriate indications and careful consideration of contraindications 1
- Proper supervision by trained personnel 1
- Appropriate technique and safety measures 1
Common Pitfalls
- Do not perform standard exercise ECG in patients with uninterpretable baseline ECG (left bundle branch block, paced rhythm, digoxin use, resting ST changes) without adding an imaging modality 2, 4
- Avoid testing when results will not change management decisions 2
- Never test patients with acute coronary syndrome, decompensated heart failure, severe aortic stenosis, uncontrolled arrhythmias, or severe hypertension (≥200/110 mmHg) 2, 4
- Recognize that negative findings do not exclude coronary disease, particularly in patients with atypical chest pain 5