The Dobutamine Stress Echocardiogram
What is a stress echocardiogram?
The test is used to evaluate your heart and valve function when you are unable to exercise on a treadmill or stationary cycle. Patients with narrowing or blockage of their coronary arteries may have minimal or no symptoms during resting. However, symptoms and signs of heart disease such as chest pain may be revealed by subjecting the heart to the stress of exercise. During exercise, healthy coronary arteries dilate more than arteries that are narrowed. Normal arteries cause more blood to be delivered to heart muscle supplied by the normal artery. In contrast, narrowed arteries cause reduced flow to the heart muscle. This reduced flow causes the involved muscle to starve during exercise and may produce symptoms like chest discomfort or shortness of breath, electrocardiogram (ECG) abnormalities and reduced movement of the heart muscle. This can be recognized by examining the movement of the walls of the left ventricle by echocardiography.
What should I do before my test?
- You should allow one hour for your appointment.
- Wear comfortable clothing.
- Do not eat for a minimum of 4 hours before the test. If your appointment is in the morning, do not eat after midnight the night before your test.
- If you are diabetic, juice is allowed in the morning with insulin (1/2 dose). If you take pills to control your blood sugar, do not take your medication until after the test is complete.
- Please do not drink tea or coffee on the day of the test, unless decaffeinated.
- Please bring along a list of tablets you are currently taking and any inhalers ie Ventolin. Continue to take your usual medication unless advised otherwise by us. You may be asked to stop some or all of your heart drugs (especially Beta Blockers) for 48 hours before the test. If so, you should start them again after the test, unless told otherwise.
- You should inform the staff performing the test if there has been any change in your symptoms since you were last seen.
How is the stress echocardiogram performed?
You will be brought to the Echo room where a routine "resting" echocardiogram is performed. Here you will be asked by your physiologist to take your top clothes off (gowns will be provided on request) and lye on your left side in a sitting position on an examination table . Three small patches (electrodes) will be attached to various parts of your chest and arms, these help to record the electrocardiogram (ECG) during the test.
The physiologist will then place a small transducer on your chest with a little amount of gel. Recordings and photos are taken from different parts of the chest to obtain several views of the heart. Particular attention is paid to the movement of all walls of the left ventricle. You may be asked to move onto your back and to the side. You may also be instructed to breathe slowly or to hold your breath. This helps in obtaining higher quality pictures. The images are constantly viewed on the monitor. During the examination the physiologist will record the blood flowing through the chambers and valves of your heart which produces a 'whooshing' sound that you will be able to hear.
An intravenous line (IV) will be inserted into a vein in your arm so the dobutamine medication can be delivered directly into your bloodstream.
Your doctor will begin the infusion of dobutamine while the physiologist continues to record echo images. The medication will cause your heart to respond but increasing your heart rate as if you were exercising. The dobutamine may give you a warm, flushing feeling and some patients experience a mild headache.
Throughout the test, the doctor and the physiologist will ask how you are feeling. Make sure to tell them if you feel chest, arm or jaw pain or if you are, short of breath, dizzy or feel lightheaded.
The IV line will be removed from your arm at the end of your test, your heart rate should return to normal in about 5 to 10 minutes. After the test, you may get dressed and go home.
How long does the test last?
The appointment will take about one hour. The actual infusion time is usually about 15 minutes. You should plan to stay in the waiting room for at least 30 minutes after completing the procedure, or until all of the symptoms you experienced have resolved.
How safe is stress echocardiography?
Since the test involves stressing the heart, there is a very small risk of causing a change in heart rhythm or very rarely a heart attack. However, even in patients who have recently experienced a heart attack, the chance of a serious problem occurring during a test is very small. You will be carefully observed during the test and treatment will be available should you require it.