What is this test?
This is an ultrasound test that uses a medicine called dobutamine to determine if the heart is getting enough blood with a fast heart beat. The test uses sound waves to obtain moving pictures of the heart. A machine generates these sound waves, called ultrasound, and then listens for the return of these sounds as they bounce back from the walls and valves of the heart, in the same way you would listen for an echo bouncing back to your ears from a distant cliff. The machine interprets the sounds to create a picture of your heart on a monitor. These pictures are recorded onto videotape or into a computer. These pictures of the heart are obtained at rest and after dobutamine has been given in an arm vein to make your heart beat quickly.
How is this test performed?
Electrical wires, called electrodes, are painlessly stuck onto your skin. You will be then asked to lie on your back as an intravenous (IV) is started in your arm. Then a sound producing probe is put on different parts of your chest to allow a specially trained technician to obtain pictures of your heart. For most people, the test is painless. If your chest is sensitive to touch, please let us know before the test or if you are having discomfort during the procedure, or if you are unable to assume certain positions. After the resting pictures are obtained, a small and continuous amount of dobutamine will be administered. Gradually, as the dose of dobutamine is increased, your heart will beat more quickly and strongly, as if you were exercising, though you will be lying on the bed throughout the test. If it is safe, or necessary, other medicine will be given to increase your heart rate. A special echo contrast agent is often given to obtain better images of the heart. You will be monitored closely for your heart rate and rhythm and symptoms. Most patients are aware of the fast beating of the heart during the test. When your heart is beating fast, more ultrasound pictures will be obtained and then the dobutamine will be stopped.
What will it show?
The test will show size and function of your heart at rest and at a fast heart rate. Normally the heart beats stronger when it beats fast because of dobutamine. If part of your heart lacks blood or is weakened for other reasons, then dobutamine may cause that part of the heart muscle to pump or contract less strongly than other parts of the heart that are receiving enough blood. This change in heart function can be seen by comparing the pictures of your heart at rest and with dobutamine. Changes in your electrocardiogram and heart rhythm will also be recorded and noted by the cardiologist.
Patient preparation and recovery
Please bring a list of your medications and bathe prior to the test as you will need to completely disrobe from the waist up. With the exception of deodorant, please do not apply lotions, oils, powder, or perfumes after bathing. A hospital gown will be provided for women or as needed. It is also advisable to go to the restroom just before the test so that you not be distracted by this need during the test. Fasting is required 4 hours prior to the test, though medications can be taken with sips of water. You will be able to rest for 10 minutes after the test is finished. No special recovery is otherwise needed, though you may be tired.