Cardiac Stress Testing

The three tests, and what each one detects

Pharmacological stress is used where the patient cannot exercise adequately — peripheral arterial disease, arthritis, deconditioning, neurological limitation. It answers the ischaemia question but tells you nothing about exercise capacity, which is precisely what a physiotherapist wanted from the test. That is worth noticing when you read the report.

Where the exercise ECG now sits

Its role in stable chest pain has narrowed considerably. Both the 2021 AHA/ACC chest pain guideline and the 2024 ESC chronic coronary syndromes guideline favour anatomical imaging (CT coronary angiography) or a functional imaging test over the plain exercise ECG for diagnosis, because its sensitivity and specificity are modest and it is uninterpretable in the presence of left bundle branch block, a paced rhythm, pre-excitation, digoxin or significant resting ST changes.^1,2

It retains real value for three purposes, all of which matter to us more than the diagnostic question: reproducing the symptom, measuring functional capacity in METs, and observing the haemodynamic and rhythm response to exertion. The 2024 guideline recommends it for precisely that in selected patients rather than discarding it, and keeps it as an alternative where imaging is unavailable.^2,3

Contraindications

Relative contraindications include known left main stenosis, moderate-to-severe aortic stenosis with uncertain symptoms, tachy- or bradyarrhythmias, hypertrophic cardiomyopathy, high-degree AV block and severe uncontrolled hypertension — each a judgement call rather than a bar.³

When the test is stopped

These are the absolute indications for terminating a symptom-limited maximal test, and they are the same signals that should stop a rehabilitation session — which is why they are worth knowing by heart rather than looking up.^3,4

• A fall in systolic blood pressure of >10 mmHg despite an increase in workload, accompanied by other evidence of ischaemia — the most ominous single sign, indicating the heart cannot sustain output. Note the criterion is the failure to rise against rising work, not simply a reading below baseline.
• Moderate-to-severe angina.
• Central nervous system symptoms — ataxia, dizziness or near-syncope.
• Sustained ventricular tachycardia, or another arrhythmia — including second- or third-degree atrioventricular block — that interferes with the normal maintenance of cardiac output during exercise.
• ST elevation >1.0 mm in leads without pre-existing Q waves from prior infarction, other than aVR, aVL or V1.
• Signs of poor perfusion — cyanosis or pallor.
• Technical difficulty monitoring the ECG or the systolic blood pressure. If the trace or the pressure cannot be read, the test cannot be supervised, so it stops on the same footing as a clinical sign.
• The patient asks to stop. That is always sufficient.

Reading the report

What it gives physiotherapy

For cardiac rehabilitation this is the single most useful document in the file, because it converts directly into a prescription:

• Set intensity from measured peak — commonly 40–80% of heart rate reserve, or a rating of perceived exertion of 11–14, anchored to what the patient actually achieved rather than an age formula.
• Respect the ischaemic threshold if one was demonstrated, and record it in the plan so every clinician works to the same ceiling.
• Note the reason the test stopped. Leg fatigue, claudication and breathlessness each point at a different limiting system and a different programme.
• Beta blockade changes the arithmetic. Peak and target heart rates are blunted, so RPE and the talk test carry more weight; if the drug was started or changed after the test, the numbers no longer transfer.
• Check the date and the medication list before prescribing from an old report.

What to tell the patient

• Comfortable shoes and clothing; nothing to eat for 2–3 hours beforehand.
• Ask the referrer whether to withhold beta blockers — sometimes required, and never something to decide yourself.
• It should feel hard; the aim is a genuine peak, not comfort. Say straight away if there is chest tightness, dizziness or unusual breathlessness.
• Electrodes and a chest that may need shaving; the treadmill gets faster and steeper in stages.
• Perfusion imaging involves an injection and a longer visit, sometimes across two appointments.

Prescribing exercise from the result

A stress test defines the ischaemic threshold and the safe ceiling; training is then prescribed below it, conventionally at 10 bpm under the heart rate at which ischaemia, arrhythmia or symptoms appeared. ⚠ Most cardiac patients are beta-blocked, so heart-rate targets are frequently invalid — prescribe by workload and Borg score instead. See prescribing exercise from test results.

References & evidence base

1. 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. Circulation. 2021;144(22):e368–e454.
2. 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. Supersedes the 2019 guideline.
3. Fletcher GF, Ades PA, Kligfield P, et al. Exercise standards for testing and training: a scientific statement from the American Heart Association. Circulation. 2013;128(8):873–934.
4. American College of Sports Medicine. ACSM’s Guidelines for Exercise Testing and Prescription. 12th ed. Philadelphia: Wolters Kluwer; 2024.
5. Cole CR, Blackstone EH, Pashkow FJ, Snader CE, Lauer MS. Heart-rate recovery immediately after exercise as a predictor of mortality. N Engl J Med. 1999;341(18):1351–1357.
6. Mark DB, Shaw L, Harrell FE, et al. Prognostic value of a treadmill exercise score in outpatients with suspected coronary artery disease. N Engl J Med. 1991;325(12):849–853.

References are numbered in citation order (Vancouver/BMJ style) and were current at the time of writing. Guidelines are living documents — verify against the latest version before clinical use.