The exercise stress test

Fig. 64.2 Presence of epicardial coronary artery disease (CAD) related to age and sex (a) women, (b) men, (c) symptoms and (d) ECG changes.


Probably no test is as used and abused as the exercise stress test (EST). The test has four aims:

  • To diagnose/rule out coronary disease. Compared to the ‘gold’ standard (coronary angiography) the EST has a sensitivity of 70% and a specificity of 80% (nuclear myocardial perfusion imaging has a higher sensitivity at = 85%, and specificity at = 90%). The problems therefore in using the EST to diagnose ishaemic heart disease (IHD) are: (i) those with coronary disease may have a normal test; (ii) those without IHD may have an abnormal test, i.e. significant ST depression (due to female sex, left ventricular [LV] hypertrophy, digoxin or idiopathic). Thus, though the diagnostic role of the EST is useful, it does have major limitations.
  • To estimate prognosis, probably its major function (see below).
  • To objectively measure exercise capacity (often serially to document changes over time). This is a very helpful function, especially when there is variance between clinical findings and reported exercise capacity. Exercise stress testing combined with gas exchange measurement provides evidence as to the physical fitness of the subject.
  • To provoke arrhythmias, useful in patients with effort related palpitations, especially in structural heart disease.


The indications for stress testing reflect the utility of the test, as outlined above. In practice, tests are usually carried out: (a) to determine whether someone with an intermediate probability of coronary disease and symptoms compatible with coronary disease actually has coronary disease (e.g. middle-aged men with a few risk factors, middle-aged women with substantial risk factors); (b) to assess prognosis in those known to have coronary disease, e.g. post-acute coronary syndrome (ACS) risk stratification.


Most tests are performed using a motorized treadmill, which increases speed and inclination according to the protocol used. A static bicycle ergometer is occasionally used. Blood pressure (BP) is measured every few minutes. A 12-lead ECG is recorded at the start (lying and standing), every minute during the test, and for at least 5 min after the test (or longer until symptoms/ECG changes resolve). Patients exercise:

1 Until symptoms force them to stop. One should carefully ascertain exactly what these symptoms are, because their exact nature impacts on the interpretation of the test, e.g. with similar ST segment depression, typical angina provoked by the test increases the probability of coronary disease compared to either atypical angina or no symptoms.

2 Until pre-specified increases in heart rate have occurred, or excess increases/decreases in BP.

3 If substantial ST depression occurs (usually ≥ 3–4 mm).

4 If significant arrhythmias occur (e.g. atrial fibrillation [AF], supraventricular tachycardias [SVTs], obviously ventricular tachycardia/ ventricular fibrillation [VT/VF]).


The interpretation depends on the pre-test probability of disease and the test findings:


A high-level (i.e. ≥ end of stage III of the Bruce protocol) negative (i.e. no ST changes or symptoms) EST is associated with a very good outlook. In the absence of intrusive symptoms further tests for coronary disease are usually not required. A low-level (i.e. stage I or II) positive test (i.e. ≥ 2 mm ST depression with typical angina symptoms) is associated with a reduced outlook, and normally leads on to coronary angiography. Intermediate tests either lead on to nuclear myocardial perfusion scans (thallium or myoview) (few symptoms) or coronary angiography (the more symptomatic, those with more risk factors or impaired LV function).

Risks and complications

The risk of death is 1 per 10 000 in outpatients, 3 per 10 000 with a recent myocardial infarction (MI). There is a higher risk of inducing MI, arrhythmias (SVT, AF and VT/VF). To minimize risks, it is important to avoid EST in those with symptomatic aortic stenosis, ≤ 2 days from a small MI, ≤ 5–7 days from a larger MI, ACS with ongoing chest pain (i.e. chest pain within 48 h), uncontrolled heart failure, uncontrolled arrhythmias (e.g. AF with a fast heart rate response), febrile patients, gross hypertension (≥ 200/120 mmHg) or in haemodynamic disturbance (e.g. due to pulmonary embolism).

Fig. 64.3 (a) Exercise protocols, and equivalent clinical states and metabolic expenditure. (b) Bruce protocol exercise test.


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Aug 29, 2016 | Posted by in CARDIOLOGY | Comments Off on The exercise stress test

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