Indications and Usefulness of Stress Echocardiography

Stress echocardiography is a sophisticated and highly specialized form of stress testing. The principles involve the direct echocardiographic visualisation of systolic thickening of the left ventricle, both at rest and under haemodynamic stress.This is done  by either physical stress (treadmill) or chemical stress (dobutamine is commonly used in Australia).

Stress echocardiography has a higher sensitivity and specificity for the detection of ischaemic heart disease than standard exercise testing, comparable to nuclear stress testing. It is commonly used to investigate for ischaemic heart disease where the resting ECG shows changes that would make a standard exercise test either difficult to interpret or uninterpretable eg ST-T changes and left bundle branch block. It is often used to rule out significant ischaemic heart disease where a standard stress test may have shown ST changes that are thought to be a “false positive change”. Such changes are more common in women, and also those with hypertension and associated left ventricular hypertrophy.

Dobutamine stress echocardiography is commonly used where a patient is unable to exercise due to physical factors eg immobility. Given its higher sensitivity than standard stress testing, stress echocardiography is also used by many cardiologists to investigate patients where a standard stress test has not shown any diagnostic ECG changes but clinical suspicion is high. Other uses include the localisation of ischaemia prior to planned intervention; with either the percutaeous approach ie angioplasty and stenting, or coronary bypass surgery, in an effort to assess the location and extent of ischaemia. It also has carries a wealth of data on assessing prognosis in ischaemic heart disease. Specialized uses include the assessment of valvular heart disease, and the assessment of suspected left ventricular outflow tract obstruction, as well as in suspected pulmonary hypertension. It can also give important information about myocardial viability that is invaluable in clinical decision making with regards the appropriateness of angioplasty/stenting, bypass surgery and aortic valve replacement.  Newer developments with digital technology enable more detailed assessment using tissue harmonic imaging and quantitative methodology eg strain rate imaging.

Disclaimer:
The purpose of this document is to provide general information regarding some aspects of cardiology for medical practitioners.  The information contained in this document is of a general nature only and does not purport to take into account, or be relevant to, the circumstances of a particular patient.  SA Heart and the author(s) of this document assume no responsibility whatsoever if all or any part of this information or advice is relied on, or acted upon, by any medical practitioner or any other member of the public.  Medical practitioners and non medically qualified individuals should seek professional advice from suitably qualified cardiologists in relation to the diagnosis and treatment of cardiac conditions.