Echocardiography uses ultrasound waves (high-frequency sound waves) to assess the motion of heart muscle and blood vessels.
Dobutamine stress echocardiography (DSE) is a non-exercise stress test that allows the cardiologist to study the capacity and reserve of heart muscle function under stressful condition. Dobutamine, a cardiac medication, is infused through a vein in increasing doses to stimulate the heart to beat faster and harder. Ultrasound images are then obtained to study the heart’s function during the infusion of dobutamine. These are then compared to the images obtained at rest to determine if any part of heart contracts abnormally.
When the heart or coronary arteries are narrowed, the heart muscles may receive adequate blood supply in the resting state. However, the blood flow may be insufficient to meet the increasing oxygen demands of the heart muscles during stress. This relative lack of blood supply causes cardiac chest pain and may be a warning sign of a heart attack. DSE is a safe test for inducing cardiac chest pain. DSE is also much more accurate than an ordinary treadmill exercise electrocardiogram (ECG) test for detecting narrowing of the underlying coronary arteries (the heart’s blood vessels).
The test is performed in the Clinic Echo Laboratory. Test will last about one-hour, you will be lying mostly on your left side and you may be asked to hold your breath for short periods of time. The doctor supervising the test will explain the procedure and you will also be required to sign a consent form before the test.
For infusion of dobutamine, an intravenous canula is inserted into one of the veins of your handbefore the examination. Multiple ECG leads will be placed on your chest to monitor the heart rhythm; excess chest hair may sometimes have to be shaved. Your blood pressure and ECG will be monitored throughout the test. To improve contact for the ultrasound probe gel is applied to your chest. A cardiac technologist will then place the probe on your chest to obtain the best possible ultrasound images before, during and after dobutamine infusion.
It is normal to feel your heart beating faster and harder during the examination. You may also feel a little short of breath. These will resolve once the infusion is discontinued. Sometimes, another medication called atropine may then be injected if necessary.
At the end of the examination, the technologist will help you clean up the gel, which is water soluble easily wiped or washed off. The ECG leads and intravenous needle will be removed. You will need to rest for at least 30 minutes to 1 hour before leaving the hospital.
Please arrive 15 minutes prior to your scheduled appointment time for registration and test preparation.
Patients who have prostate problems or glaucoma (a condition causing eye pain due to excessively high pressure in the eyeball) should not receive atropine. Please inform the technologist or doctor supervising the test if you have these conditions.
Ultrasound is extremely safe and has no material side effects, even with repeated examinations.
Possible adverse effects of dobutamine include palpitations, chest pain, shortness of breath, nausea, vomiting, dizziness and flushing. These are transient and will disappear within minutes after the test is completed. Leakage of the drug at the infusion site may cause local pain and inflammation.
Atropine may cause blurring of vision, dry mouth, flushing, abdominal discomfort and retention of urine (1%). Because atropine persists for longer in the body than dobutamine, these symptoms may last up to few hours after the test.
If ultrasound contrast agent is used during the procedure, you will be monitored for any allergic or adverse drug reaction after the procedure.
Major complications are very rare. Heart attack (Acute myocardial infarction 0.1%) and severe heart rhythm abnormality (Life threatening heart rhythm <0.2%), death (0.002%) have been reported. Various medications are available to counter these problems in the unlikely event of their occurrence. If you feel chest pain or any other discomfort during the test, please inform the technologist or supervising doctor.
The supervising doctor will need to review recorded computed images and ECG recordings of the DSE procedure. Your doctor will inform you of the results, usually at your next outpatient clinic visit. A formal report should be available in 24-48 hours. You may be contacted earlier if there is a severe abnormality or if an urgent management decision is required pending the results.