Stress Echocardiography

Why are you being sent for a stress echocardiogram?

As coronary artery disease (CAD) progresses, the heart muscle may not receive enough blood supply when under stress.  This often results in chest pain (angina pectoris) or shortness of breath. On the other hand, there may be no outward physical signs of significant disease. If CAD is limiting blood flow to part of your heart, the stress echocardiogram test may be useful in detecting the presence and significance of CAD.  Valvular disease may also cause symptoms of shortness of breath that can equally be evaluated by this test.

What is a stress echocardiogram and what does it show?

A stress echocardiogram is a diagnostic imaging study that uses ultrasound waves to produce images of the heart muscle. During an echocardiogram, a small device called a transducer is held against the chest. The transducer sends ultrasound waves that reflect (echo) off the various parts of the heart. The echoes are converted into moving images of the heart. These images are displayed on a screen and are digitally recorded.  An echocardiogram is first done while your heart is "resting." When combined with the stress component, either through exercise or use of an intravenous pharmacological agent (Dobutamine), the echocardiographic stress images can help determine if the heart muscle is getting sufficient blood supply.  Normally, all areas of the heart muscle pump more vigorously during stress. If an area of the heart does not pump as well as it should during the stress component, this often indicates that it is not receiving enough blood because of a blocked or narrowed artery. However, it does not provide images of the actual coronary arteries. If your doctor suspects blocked or narrowed arteries, additional tests may be recommended.

TREADMILL STRESS ECHOCARDIOGRAPHY

How is the test performed?

Electrode patches will be attached to your body. These patches are connected to the ECG monitor, which will record your heart rate, rhythm, and possible electrical changes throughout the test. “Resting” echo images will be first taken of your heart.  You will then be asked to begin exercising on the treadmill with the goal of performing as much exercise as you can tolerate. Eventually you will become tired or have clinical reasons that require the treadmill to be stopped.  You will then immediately get off the treadmill and lie down on the scanning table without a “cool down” prior to the treadmill being completely stopped so that pictures of your heart can be quickly obtained. 

DOBUTAMINE STRESS ECHOCARDIOGRAPHY

What is a Dobutamine Stress Echo?

A Dobutamine stress echocardiogram ("echo") is a test that combines an ultrasound study of the heart with a drug-induced stress test. The test allows doctors to learn how the heart functions when it is made to work harder.  Generally, a stress test is performed while patients walk on a treadmill or ride a stationary bicycle. For patients who are unable to adequately exercise, the test may be done by injecting Dobutamine intravenously, a drug that produces an effect on the heart similar to exercise.  Dobutamine is infused (injected slowly) into a vein in your arm. This potent drug causes your heart to pump faster and harder. Additional echo images are then obtained during and after the infusion of Dobutamine.

Preparing for the test

• Do not eat or drink 4 hours prior to the test. This will help prevent the possibility of nausea as well as allow for improved imaging quality.
• If you are currently taking heart medications (especially beta blockers), check with your doctor. He or she may ask you to stop them a day or two before the test. This can help get more accurate test results.
• Before the test, you'll be given an explanation of the test and you'll be asked to sign a consent form. Feel free to ask any questions about the procedure.
• Only if you are undergoing a Dobutamine stress test will an intravenous (IV) line will be inserted into a vein in your arm to allow injection of Dobutamine.
• Several electrodes (small sticky patches) will be placed on your chest to obtain ECG (electrocardiogram), a recording of your heart's electrical activity.

What will I feel during the test?

You may feel tired from the exercise. The Dobutamine will make your heart beat faster and stronger almost like you were exercising even though you will be lying down comfortably.  The effect of Dobutamine can take on average 3-5 minutes to dissipate.  Additionally, some people with sensitive skin have reported slight irritation from the electrode patches; skin cream or lotion can help reduce irritation after the patches are removed.