As with other stress tests, an exercise echocardiogram shows how your heart functions when it is working harder. It is most often done to con- ?rm or rule out coronary artery disease. The moving image enables your doctor to see where blockages are occurring.
A stress echocardiogram may be done in a doctor’s of?ce or a hospi- tal. The test has two parts. First, the technician does a resting echocar- diogram (ultrasound of the heart) while you lie on a table. Then you get on a treadmill or a stationary bicycle and exercise until your heart is working to maximum. A second echocardiogram is done while your heart rate is still high. The test will show if there are any exer- cise-induced changes in your heart in the results of the echocardiogram. For example, in areas of the heart where the blood supply is limited because of obstructions of the blood vessels to the heart muscle, that area may not contract as well as it should. In another example, an exercise- induced abnormality not present when the heart is at rest suggests reversible blood ?ow abnormalities and the need for treatment to prevent a heart attack.

Chemical Stress Testing

If a disability (for example, arthritis, back trouble, or a stroke) prevents you from exercising for a stress test, your doctor can use intravenous medication to increase your heart rate combined with an imaging tech- nique such as echocardiography to see how your heart functions when it’s working harder. This method is called chemical or pharmacologic stress testing. The medications most commonly used are dobutamine, dipyridamole, or adenosine.
The drugs are administered so that your heart rate increases gradu- ally. If you are able to do some exercise, you may be asked to walk on a treadmill for a minute or so after the drug is injected. Trained medical assistants will monitor you throughout the test, and you should report any unusual symptoms. Dobutamine may cause a marked increase in blood pressure or an arrhythmia. Adenosine may cause a brief, passing slowing of the heart rate. Both adenosine and dipyridamole can cause wheezing and should be used cautiously, if at all, in people with asthma or chronic obstructive pulmonary disease. The drugs can be stopped at any time.
Preparation for a chemical stress test is similar to regular stress test- ing. You will be asked not to eat or drink anything for at least 3 hours before the test, in order to avoid nausea. If you take medications, be sure to talk to your doctor about what to do; you may need to stop tak- ing them for an interval before the test. If you have diabetes and take insulin, you will need speci?c instructions. If you have any history of asthma, bronchitis, or emphysema, tell your doctor, because some stress-inducing medications may be harmful to you.