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# Exercise and pharmacological stress testing

- Investigation

The heart is made to work harder, by walking on a treadmill or with a drug, while an ECG or a scan looks for a part that runs short of blood.

Updated Nov 13, 2026

## Key points

- Positive exercise ECG: at least 1 mm horizontal or downsloping ST depression, measured 60–80 ms after the J point.
- An adequate test reaches at least 85% of the age-predicted maximal heart rate (220 minus age); a negative test below it is inconclusive.
- Cannot exercise or resting ECG not readable (LBBB, paced, WPW, digoxin): use pharmacological stress with imaging.
- Vasodilators (adenosine, dipyridamole) cause bronchospasm and AV block; avoid them in active bronchospasm and stop caffeine beforehand.
- High-risk signs: early or deep ST depression, ST elevation without Q waves, fall in blood pressure, sustained ventricular arrhythmia.

On this page

- The basics Key points
- What it is
- Indications
- Preparation and what happens
- Next step
- Memory aid
- Elsewhere in DurgiPedia

- Clinical Choosing the stress test (local availability also decides)
- Risks and complications

- Safety Contraindications

- Study Test yourself

- Connections Connections

## What it is

A stress test asks whether the coronary arteries can meet a higher demand. At rest a narrowed artery may still supply enough blood; when the heart rate and blood pressure rise, the muscle beyond it becomes ischaemic, and that shows as chest pain, ST depression on the ECG, a wall that stops moving well on echocardiography, or a defect on a perfusion scan. In the exercise ECG test the patient walks on a treadmill (or pedals a bicycle) in stages that get faster and steeper, most often the Bruce protocol, while the 12-lead ECG, blood pressure and symptoms are watched; the aim is to reach at least 85% of the age-predicted maximal heart rate. It is cheap and also measures exercise capacity, but its accuracy is only moderate and it needs a readable resting ECG. When the patient cannot exercise, or the resting ECG hides ischaemia (left bundle branch block, paced rhythm, pre-excitation, digoxin, resting ST depression), the stress is added with a drug and the answer comes from imaging: vasodilators (adenosine, regadenoson, dipyridamole) with a nuclear perfusion scan, or dobutamine, which raises heart rate and contractility, usually with echocardiography. The requesting doctor does not run the test but must choose the right one, explain it, prepare the patient and act on the report.

## Indications

- Diagnosis of coronary artery disease in a patient with exertional chest pain and an intermediate pretest probability.
- Risk stratification of known stable coronary disease, or after an acute coronary syndrome once the patient is stable and pain-free.
- Measuring exercise capacity and the blood pressure and heart rate response (chronotropic incompetence).
- Symptoms or arrhythmias that appear only on exertion, such as exercise-induced palpitations or syncope.
- Pharmacological stress with imaging: patients who cannot walk enough, or whose resting ECG cannot show ischaemia.

## Contraindications

- Acute myocardial infarction in the first days, or an acute coronary syndrome that is not yet stable.
- Uncontrolled arrhythmia with symptoms or haemodynamic compromise; decompensated heart failure.
- Symptomatic severe aortic stenosis, acute aortic dissection, acute pulmonary embolism, acute myocarditis or pericarditis.
- Relative: known left main stenosis, severe resting hypertension, hypertrophic cardiomyopathy with outflow obstruction, high-degree AV block.
- Vasodilator stress: active bronchospasm, second- or third-degree AV block or sick sinus without a pacemaker, hypotension, recent caffeine.
- Dobutamine stress: severe hypertension, significant tachyarrhythmias, dynamic outflow obstruction.

## Preparation and what happens

- Choose the test: exercise ECG if the patient can walk and the resting ECG is readable — otherwise imaging or a drug is needed.
- Explain what will happen and obtain consent — the patient should know the test can provoke symptoms and can be stopped at any time.
- Give clear instructions about anti-anginal drugs and beta-blockers — they blunt the heart rate and can mask ischaemia; follow the requesting team.
- Ask the patient to avoid caffeine before a vasodilator test, and to come with a light meal and walking shoes — caffeine blocks the drug.
- A resting ECG and blood pressure are recorded first — they are the baseline for every later change.
- The patient walks in stages that get faster and steeper while ECG, blood pressure and symptoms are monitored — ischaemia appears as demand rises.
- The test stops at the target or at a stop criterion: limiting angina, ST elevation, falling blood pressure, serious arrhythmia or exhaustion.
- Monitoring continues for several minutes in recovery — some ischaemic changes and arrhythmias appear only after exercise.
- In pharmacological stress the drug is given through a cannula and images are taken at peak stress and at rest — the two are compared.

## Choosing the stress test (local availability also decides)

| Situation | Usual choice | Why |
| --- | --- | --- |
| Can exercise, normal resting ECG | Exercise ECG (treadmill) | Simple, cheap, measures exercise capacity |
| Can exercise, resting ECG not readable (digoxin, resting ST depression, WPW) | Exercise with echocardiography or perfusion imaging | ST changes cannot be read; imaging shows the ischaemia |
| Left bundle branch block or paced rhythm | Vasodilator perfusion imaging | Exercise causes septal artefacts in this setting |
| Cannot exercise | Vasodilator perfusion or dobutamine echocardiography | The drug replaces the exercise |
| Active bronchospasm or high-degree AV block | Dobutamine rather than adenosine or dipyridamole | Vasodilators worsen bronchospasm and AV block |

## Risks and complications

- Serious complications (infarction, sustained arrhythmia, death) are rare when the contraindications are respected.
- Vasodilators: flushing, chest tightness, breathlessness, headache, bronchospasm and transient AV block; aminophylline reverses them.
- Dobutamine: palpitations, ventricular ectopy, atrial fibrillation, hypotension or hypertension; it is stopped and a beta-blocker can reverse it.
- Falls on the treadmill and musculoskeletal pain; radiation exposure in nuclear perfusion imaging.
- False positives: digoxin, left ventricular hypertrophy, hypokalaemia, resting ST changes, more often in women; false negatives: submaximal effort, beta-blockers.

## Next step

- High-risk result (early or deep ST depression, ST elevation, hypotension, large perfusion defect): refer urgently to cardiology for coronary angiography.
- If chest pain or ST changes persist in recovery, treat it as an acute coronary syndrome: 12-lead ECG, troponin and call a senior at once.
- Low-risk result: optimise medical treatment and risk factors; review if symptoms change.
- Inconclusive test (target heart rate not reached, uninterpretable ECG): repeat with imaging or pharmacological stress.
- Tell the patient when to restart any drug that was held, and give the result with a written plan at follow-up.

## Memory aid

Stop the treadmill for the four Ps: Pain that limits, Pressure that falls, a Pattern of ST elevation, and Pulse disorders (sustained arrhythmia).

## Test yourself

Think of the answer, then tap the question to see it.

## A 58-year-old with exertional chest pain and left bundle branch block needs a stress test. Which test is best and why?

Pharmacological stress with a vasodilator and perfusion imaging. LBBB makes the ST segments unreadable, and exercise in LBBB causes false septal perfusion defects.

## What counts as a positive exercise ECG for ischaemia?

At least 1 mm of horizontal or downsloping ST depression 60–80 ms after the J point, especially with typical chest pain. ST elevation in leads without Q waves suggests transmural ischaemia.

## A patient on a beta-blocker stops at 70% of the predicted maximal heart rate with no ST change. How should the result be reported?

As inconclusive, not negative: the target of 85% was not reached. Repeat with imaging or pharmacological stress, or after the drug is held as the requesting team directs.

## During an adenosine stress test the patient develops wheeze and second-degree AV block. What is the mechanism and the response?

Adenosine acts on A1 receptors in the AV node and A2B receptors in the airway. Stop the infusion (its effect is brief), and give aminophylline and a bronchodilator if symptoms persist.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/clinical-skills/exercise-and-pharmacological-stress-testing/)

## Elsewhere in DurgiPedia

- [Muscle blood flow and the cardiovascular response to exercise](https://durgical.com/en/physiology/muscle-blood-flow-and-the-cardiovascular-response-to-exercise/)
- [Coronary circulation and myocardial ischemia](https://durgical.com/en/physiology/coronary-circulation-and-myocardial-ischemia/)
- [The ECG in ischemia and infarction](https://durgical.com/en/physiology/the-ecg-in-ischemia-and-infarction/)
- [Recording a 12-lead ECG](https://durgical.com/en/nursing/recording-a-12-lead-ecg/)

## Connections

## Related 6

- [Reading an ECG step by step](https://durgical.com/en/clinical-skills/reading-an-ecg-step-by-step/)
- [STEMI and its territories, and STEMI mimics](https://durgical.com/en/clinical-skills/stemi-and-its-territories-and-stemi-mimics/)
- [Right and left bundle branch block and fascicular blocks](https://durgical.com/en/clinical-skills/right-and-left-bundle-branch-block-and-fascicular-blocks/)
- [Echocardiography: transthoracic and transoesophageal](https://durgical.com/en/clinical-skills/echocardiography-transthoracic-and-transoesophageal/)
- [Coronary angiography and angioplasty](https://durgical.com/en/clinical-skills/coronary-angiography-and-angioplasty/)
- [Troponin and natriuretic peptides](https://durgical.com/en/clinical-skills/troponin-and-natriuretic-peptides/)

## Related conditions 6

- [Stable angina](https://durgical.com/en/conditions/stable-angina/)
- [Myocardial Infarction (Heart Attack)](https://durgical.com/en/conditions/myocardial-infarction/)
- [Aortic Valve Stenosis](https://durgical.com/en/conditions/aortic-valve-stenosis/)
- [Hypertrophic cardiomyopathy](https://durgical.com/en/conditions/hypertrophic-cardiomyopathy/)
- [Heart failure](https://durgical.com/en/conditions/heart-failure/)
- [Asthma](https://durgical.com/en/conditions/asthma/)

## In Pharmacology 6

- [Adenosine](https://durgical.com/en/pharmacology/adenosine/)
- [Dobutamine](https://durgical.com/en/pharmacology/dobutamine/)
- [Dipyridamole](https://durgical.com/en/pharmacology/dipyridamole/)
- [Aminophylline](https://durgical.com/en/pharmacology/aminophylline/)
- [Beta blockers](https://durgical.com/en/pharmacology/classes/beta-blockers/)
- [Organic nitrates](https://durgical.com/en/pharmacology/classes/organic-nitrates/)

[← All clinical skills](https://durgical.com/en/clinical-skills/)

Educational content; it does not replace supervised hands-on training, your institution's protocols or a prescriber's order. A procedure is learnt with a teacher and done only once you are trained to do it.

Sources: [Treadmill Stress Testing](https://www.ncbi.nlm.nih.gov/books/NBK499903/) (StatPearls (NCBI Bookshelf), 2023); [Nuclear Medicine Stress Test](https://www.ncbi.nlm.nih.gov/books/NBK557682/) (StatPearls (NCBI Bookshelf), 2025).

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Representative model, for educational purposes only.

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/clinical-skills/exercise-and-pharmacological-stress-testing/