Sloane Street Investigations Echocardiography and Stress Echo Services

An echocardiogram is a painless procedure. You will lie down on the couch turning slightly on your left side. Some gel is placed on your chest to make better contact with the transducer or probe. It emits ultrasound waves which pass harmlessly through the structures, bouncing back to the transducer and producing an image on the screen.

An echocardiogram will show the contraction of the heart muscle. If the patient has had a heart attack this would be shown as an area that doesn’t contract, as it is scar tissue. The echocardiogram is used to assess the opening and closing functions of the four valves. It is able to quantify the degree of severity of both the narrowing and leaking of the valves.

The Doppler ultrasound technique is additionally used to see if there is any leaking from the valves or valvular narrowing.

The test does not usually assess the state of your coronary arteries, as the coronary images are very limited. A stress echo is used to detect coronary disease.

Common indications for an Echocardiogram

• Shortness of breath - without an obvious lung cause.
• Hypertension - to see if the heart muscle has thickened (hypertrophy), meaning the blood pressure needs to be better controlled.
• Valvular disorders - when a doctor may have heard a heart murmur.
• Palpitations - feeling or having an irregular heartbeat.

Stress echo is used for the assessment of coronary arteries, also as part of a work-up for pre-operative safety and preparation.

The patient initially has a standard echocardiogram to look at the heart at rest.

The next stage is a detailed assessment of the heart’s contraction at a high heart rate. The majority of patients increase their heart rate by exercising on a static bicycle. The patient’s ECG is simultaneously monitored to look for potential ECG signs of lack of blood supply to any area of the heart muscle. Once a peak heart rate has been achieved an echocardiogram of the heart is rapidly taken.

If there is significant coronary narrowing, the images at peak exercise, will show a reduced level of contraction in the area of the heart muscle corresponding to the artery with the narrowing. In simple terms it is a very useful test to check if a patient has more than 50% narrowings in any of the three main coronary arteries. This is about the threshold at which patients may benefit from interventional techniques to help coronary arteries.

Stress echo has the similar sensitivity and specificity as MRI perfusion and a nuclear medicine technique called a myocardial perfusion scan. The difference is that stress echo has no radiation, whereas in a nuclear myocardial perfusion scan there is the equivalent of 400 chest x-rays of radiation. Separately, many patients prefer stress echo to an MRI as they may not enjoy being in a scanner.

If there is difficulty in achieving a high heart rate with exercise, a drug called Dobutamine is given to increase the heart rate. The effect of the Dobutamine, wears off within half an hour. Patients are asked to stay in the practice for about half an hour after their test.

The risks of a stress echo are the same as a standard treadmill test and exceptionally low.