Cardiac Stress Testing: A Selection Guide for Referrers
For GPs and physicians choosing between stress ECG, stress echocardiography, SPECT, PET, stress CMR — and how CCTA fits into modern test selection.
Refer a Patient Or call (02) 8401 9598 to discuss complex casesStress testing remains a cornerstone of evaluating known or suspected coronary artery disease, but the modality landscape has changed substantially. Choosing the right test now requires considering pre-test probability, the clinical question being asked, patient-specific factors, and modality availability. This page is a practical reference for GPs and physicians making that choice.
Why test selection matters
Modern guidelines have moved decisively away from a one-size-fits-all approach to ischaemia testing. The 2021 ACC/AHA chest pain guideline and the 2024 ESC chronic coronary syndromes guideline both anchor test selection on pre-test probability stratification, with modality choice tailored to the clinical question, patient-specific factors, and local availability. The wrong test produces low diagnostic yield, unnecessary downstream testing, false reassurance — or all three.
The most consequential decision is not which functional test to choose, but whether to choose a functional test at all rather than an anatomical one. That decision shapes everything that follows.
Functional vs anatomical testing
Cardiac investigation for suspected obstructive coronary artery disease falls into two categories that answer different questions:
Stress ECG · Stress echo · SPECT · PET · Stress CMR
Detect ischaemia by demonstrating reduced perfusion or wall-motion abnormality under stress. Best suited to symptomatic patients across the probability spectrum where the question is: "is there flow-limiting disease?"
CT coronary angiography · Invasive coronary angiography
Visualise the coronary arteries directly, demonstrating anatomic disease whether or not it is currently flow-limiting. Best suited to lower–intermediate probability patients where the question is: "is significant coronary disease present?"
The two are complementary. A functional test that demonstrates ischaemia confirms haemodynamic significance; an anatomical test demonstrating high-grade stenosis raises the question of functional significance. Many real-world workups combine them — CCTA followed by functional testing for intermediate stenoses, or functional testing followed by invasive angiography for high-risk findings.
For an outpatient with stable chest pain and no prior cardiac history, CCTA has become the preferred first-line investigation in many modern algorithms when pre-test probability is low to intermediate. Functional testing remains preferred when there is known coronary artery disease, when ischaemia must be documented before revascularisation, when CCTA is contraindicated or non-diagnostic, or when the clinical question concerns valve disease, exercise capacity, or pre-operative risk.
Pre-test probability framework
Both major guidelines build their selection algorithms on pre-test probability of obstructive CAD. The 2024 ESC framework collapses age, sex, and symptom typicality into a single likelihood category that drives the recommended next step.
The 2021 ACC/AHA chest pain guideline takes a parallel approach with low, intermediate, and high pre-test risk categories. Stress ECG alone is not recommended in either framework as a first-line investigation when imaging tests are available.
Modality comparison at a glance
Approximate diagnostic performance for detection of obstructive CAD, drawing on the 2018 Knuuti meta-analysis and current guideline syntheses. Real-world performance varies substantially with operator experience, image quality, and patient factors.
| Modality | Sens. | Spec. | Radiation | Best suited to | Key limitation |
|---|---|---|---|---|---|
| Stress ECG | 65–70% | 70–75% | None | Functional capacity, rhythm response, exercise-induced symptoms in normal baseline ECG. | Low diagnostic accuracy. Uninterpretable in baseline ECG abnormality, LBBB, paced rhythm, pre-excitation. |
| Stress echo | 80–85% | 80–85% | None | Symptomatic patients across probability spectrum; valve assessment under load; HFpEF work-up. | Operator dependent. Image quality affected by body habitus and lung disease. |
| SPECT MPI | ~80% | ~80% | ~6–12 mSv | Patients with poor echo windows; broad availability. | Radiation. Attenuation artefacts (breast, diaphragm) reduce specificity. |
| PET MPI | ~90% | ~85% | ~3–5 mSv | Highest nuclear accuracy. Quantitative MBF for microvascular and balanced multivessel disease. | Limited availability; cost. |
| Stress CMR | ~85–90% | ~85–90% | None | Comprehensive (ischaemia + scar + function); LBBB; complex cardiomyopathies. | Limited availability; claustrophobia and some implantable devices contraindicated. |
Performance figures represent typical ranges for detection of obstructive (≥50–70%) coronary stenosis in patients with stable symptoms. Sources: Knuuti 2018; 2021 ACC/AHA chest pain guideline; 2024 ESC CCS guideline.
Modality profiles
Stress ECG (exercise treadmill test)
Once the default first-line test, stress ECG has been progressively displaced by imaging modalities in modern guidelines because of its modest diagnostic accuracy and the high prevalence of confounding baseline ECG findings. It retains a defined but narrow role.
- Functional capacity assessment (cardiac rehabilitation, sports clearance, return to activity).
- Evaluation of exercise-induced rhythm disturbance in a structurally normal heart.
- Symptomatic patients with normal baseline ECG and intermediate probability where imaging is genuinely unavailable.
- Any baseline ECG abnormality: LBBB, paced rhythm, pre-excitation, >1 mm resting ST depression, on digoxin.
- Women at low–intermediate pre-test probability — false-positive rate is substantially higher than in men.
- Patients unable to achieve ≥85% age-predicted maximum heart rate.
- Known coronary artery disease where ischaemia localisation matters.
Stress echocardiography
Combines treadmill or pharmacological stress with echocardiographic assessment of regional wall-motion at rest and at peak stress. No radiation, broadly available, and uniquely able to evaluate valve haemodynamics under load. Diagnostic accuracy is highly dependent on image quality and on capturing post-exercise images within the narrow window before heart rate declines (typically 60–90 seconds).
Cardiologist-led acquisition matters more than the modality alone. The post-exercise window is narrow, and a delay of 30 seconds can erase a wall-motion abnormality. Stress echo run by an operator who is not also interpreting the images often produces a less diagnostically useful study. Dobutamine stress echo is the pharmacological alternative for patients who cannot exercise; it has comparable accuracy but loses the prognostic value of exercise capacity.
SPECT myocardial perfusion imaging
Established, broadly available, and accommodates patients who cannot exercise via vasodilator or dobutamine pharmacological stress. The principal limitations are radiation exposure and attenuation artefact — breast tissue in women and diaphragmatic shadowing in men can reduce specificity. CT-based attenuation correction and gated SPECT have substantially improved specificity in modern protocols.
PET myocardial perfusion imaging
The highest-accuracy nuclear modality. Beyond binary ischaemia detection, PET enables quantitative myocardial blood flow and flow reserve, which detects microvascular dysfunction and balanced multivessel ischaemia that other tests miss. Lower radiation dose than SPECT despite higher diagnostic yield. Limited availability in Australia is the main barrier to wider use.
Stress cardiac magnetic resonance (CMR)
The most comprehensive single test — perfusion (vasodilator first-pass), wall motion (dobutamine option), late gadolinium enhancement for scar, and structural assessment in one study. Particularly valuable in LBBB, prior myocardial infarction with viability questions, and complex cardiomyopathies where the differential includes infiltrative or inflammatory disease. Contraindications include severe claustrophobia and some legacy pacemakers and ICDs (most modern devices are MRI-conditional).
Selection algorithm by clinical scenario
The framework below summarises a defensible default for each common referral situation. Local availability, patient factors, and clinical judgement always modify the choice.
New stable chest pain · Low PTP (≤15%)
Defer testing if very low. CCTA preferred at 5–15%. Functional imaging acceptable. Consider CAC for risk reclassification using the MESA calcium calculator in selected patients.
New stable chest pain · Intermediate PTP (15–50%)
CCTA or functional imaging both reasonable. Stress echo or stress CMR preferred among functional options. Choose based on echo window adequacy, baseline ECG, and exercise capacity.
New stable chest pain · High PTP (≥50%)
Functional imaging to document and localise ischaemia, or proceed directly to invasive angiography in selected high-risk patients. CCTA generally not first choice — anatomy alone will not change management.
Known CAD · New or worsening symptoms
Functional imaging strongly preferred. Anatomy is already known; the clinical question is whether new ischaemia is present and where. Stress echo, SPECT, PET, or stress CMR per local availability.
Pre-revascularisation decision
Functional imaging required. Class I in both ESC and ACC/AHA guidelines for documenting ischaemia before non-emergent PCI or CABG. CCTA does not substitute.
Pre-operative risk · Non-cardiac surgery
Functional imaging in patients with poor or unknown functional capacity (<4 METs) facing intermediate–high risk surgery. Exercise stress preferred where possible — exercise capacity itself is prognostic.
Asymptomatic primary prevention
Stress testing not indicated. Consider CAC for risk reclassification in borderline–intermediate ASCVD risk, supported by the PREVENT and MESA calcium calculators.
Functional capacity / sports clearance
Stress ECG appropriate when baseline ECG is normal and the question is exercise tolerance, rhythm response, or blood pressure response — not ischaemia in a high-probability patient.
Special populations
Avoid stress ECG alone
Higher false-positive rate with stress ECG; imaging-based functional testing or CCTA preferred. Breast attenuation can reduce SPECT specificity — PET, stress echo, or CMR often preferable.
Vasodilator stress preferred
Stress ECG uninterpretable. Exercise stress with imaging produces septal artefact in nuclear studies — vasodilator pharmacological stress preferred. Stress CMR or vasodilator PET are strong alternatives.
Functional imaging required
Anatomy is misleading once revascularisation has been performed; the question is always whether ischaemia is present. Symptom evaluation requires functional imaging, not repeat anatomy.
Stress echo or CMR with viability
Stress echo or stress CMR. Consider viability assessment with CMR late gadolinium enhancement or PET in patients being considered for revascularisation.
Avoid gadolinium
Avoid gadolinium-based stress CMR. Stress echo or nuclear preferred. Be aware that obstructive CAD prevalence is high in this group; threshold for testing should be low.
Lower threshold to investigate
Silent ischaemia is common; lower threshold for testing in symptomatic patients. CCTA or PET often preferred given higher disease burden and microvascular disease prevalence.
PET, CMR, or CCTA
Stress echo often diagnostically inadequate due to poor windows. PET or stress CMR provide better image quality. CCTA viable in many cases despite body habitus.
Exercise vs pharmacological stress
Always exercise where possible. Exercise capacity is itself prognostic and provides physiological information no pharmacological agent reproduces — symptom reproducibility, blood pressure response, rhythm response under load, and METs achieved. Patients on rate-limiting agents who cannot reach 85% age-predicted maximum heart rate should have those agents withheld where clinically safe before testing.
When exercise is not feasible:
Regadenoson, adenosine, dipyridamole
Used with SPECT, PET, and stress CMR. Causes coronary vasodilation rather than physiological stress; comfortable, quick, and well tolerated. Caffeine and theophylline interfere with vasodilator action and must be withheld for 12–24 hours.
Inotropic and chronotropic stress
Used with stress echo and occasionally CMR. Increases heart rate, contractility, and afterload; closer in physiology to exercise but with more side effects and a small risk of arrhythmia. Useful when vasodilator stress is contraindicated.
Test quality and protocol fidelity
A meaningful proportion of stress tests reported as "negative for ischaemia" are not truly negative — they are inconclusive. The most common reasons are submaximal exertion, premature termination of the Bruce protocol, and failure to reach an adequate heart rate. Specificity figures in the literature assume a properly performed test. A study terminated at 75% age-predicted maximum heart rate without symptoms tells you nothing about ischaemia at peak demand.
When reviewing a report, look for:
- METs achieved — <5 METs limits ischaemia detection and is itself prognostic.
- Percentage of age-predicted maximum heart rate — ≥85% is the conventional adequacy threshold.
- Rate–pressure product at peak — useful surrogate for true myocardial demand.
- Time to symptom onset and reason for test termination.
A submaximal test in a symptomatic patient is not a negative test. It is an inconclusive one, and either repeat testing under conditions that allow adequate exertion or escalation to imaging is reasonable.
Practical referral pearls
The information on a referral changes the test choice. A few details that materially shift modality selection:
Clinical question and urgency
State what you are trying to confirm or exclude — ischaemia, valve disease, exercise capacity, pre-op risk. Urgency drives scheduling.
Baseline ECG and cardiac history
LBBB, paced rhythm, prior MI, prior revascularisation, known cardiomyopathy — each redirects the modality choice.
Mobility and exercise capacity
If the patient cannot exercise, pharmacological stress is needed and the modality choice narrows. Mention orthopaedic, respiratory, or neurological barriers explicitly.
Current medications
Beta-blockers and other rate-limiting agents may need withholding before exercise testing. Theophylline and caffeine interfere with vasodilator stress.
Rapidly progressive symptoms
Crescendo angina, rest pain, or symptoms with minimal exertion are not outpatient stress test problems. Phone the cardiologist or refer to ED.
Conflicting prior tests
Recent discordant CCTA and functional results, or prior equivocal reports, benefit from a phone discussion before another investigation is ordered.
Further reading
For detailed reference material on echocardiography measurements, normal values, and clinical thresholds, see the echocardiography reference hub. For risk stratification tools alongside test selection decisions, see the cardiovascular risk calculator hub.
This page is written for clinicians making test selection decisions. For patient-focused information about what a stress echocardiogram involves and how to prepare, see the comprehensive stress echocardiogram guide. To book a stress echocardiogram at the Westmead clinic, see the stress echocardiogram Westmead page.
References
- Gulati M, Levy PD, Mukherjee D, et al. 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain. J Am Coll Cardiol. 2021;78(22):e187–e285.
- Vrints C, Andreotti F, Koskinas KC, et al. 2024 ESC Guidelines for the management of chronic coronary syndromes. Eur Heart J. 2024;45(36):3415–3537.
- Knuuti J, Ballo H, Juarez-Orozco LE, et al. The performance of non-invasive tests to rule-in and rule-out significant coronary artery disease in patients with stable angina: a meta-analysis focused on post-test disease probability. Eur Heart J. 2018;39(35):3322–3330.
- Wolk MJ, Bailey SR, Doherty JU, et al. ACCF/AHA/ASE/ASNC/HFSA/HRS/SCAI/SCCT/SCMR/STS 2013 multimodality appropriate use criteria for the detection and risk assessment of stable ischemic heart disease. J Am Coll Cardiol. 2014;63(4):380–406.
- Pellikka PA, Arruda-Olson A, Chaudhry FA, et al. Guidelines for Performance, Interpretation, and Application of Stress Echocardiography in Ischemic Heart Disease: From the American Society of Echocardiography. J Am Soc Echocardiogr. 2020;33(1):1–41.
- Hendel RC, Berman DS, Di Carli MF, et al. ACCF/ASNC/ACR/AHA/ASE/SCCT/SCMR/SNM 2009 appropriate use criteria for cardiac radionuclide imaging. J Am Coll Cardiol. 2009;53(23):2201–2229.
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