Stress echocardiography for ischaemia and myocardial viability
THE CONTEXT
Stress echocardiography assesses myocardial contraction during pharmacological stress and can also examine viability in patients with impaired left ventricular function.
Patient selection and technique
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Stress echocardiography investigates suspected coronary artery disease when exercise stress testing is unsuitable, including in patients with mobility problems or pre-existing bundle branch block.
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Two-dimensional echocardiography is performed before and during infusion of a moderate to high dose of an inotrope such as dobutamine.
Detection of ischaemia
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Poorly perfused myocardial segments become ischaemic and contract poorly under stress.
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This impaired contraction appears as a wall motion abnormality on the scan.
Assessment of viability
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Stress echocardiography is sometimes used to assess myocardial viability in patients with impaired left ventricular function.
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Low-dose dobutamine can induce contraction in hibernating myocardium. Patients showing this response may benefit from coronary artery bypass surgery or percutaneous coronary intervention.