In stress echocardiography, detailed images of the heart are obtained before, during, and after a cardiac stress test using a device called a transducer that is placed on the chest. (The transducer emits high-frequency sound waves, or ultrasound, and converts the sound waves echoed back from the heart into images.) Exercise on a stationary bike or treadmill is the most common form of stress testing. Stress echocardiography can detect heart muscle that is not contracting as strongly as expected, indicating possible blockages in the coronary arteries.

Purpose of the Stress Echocardiography

  • To aid in the evaluation of possible coronary artery disease
  • To determine appropriate levels of exercise for people with angina (chest pain due to inadequate delivery of oxygen to the heart muscle) or other symptoms of heart disease
  • To evaluate heart function and exercise capacity after a heart attack, angioplasty, or bypass surgery
  • To evaluate the heart prior to major surgery

Who Performs It

  • A doctor assisted by a nurse or a technician

Special Concerns

  • People who cannot exercise adequately because of orthopedic, arthritic, or lung disorders may instead be given dobutamine, a drug that increases the heart rate.
  • People who have unstable angina or severe aortic valvular heart disease may not be able to undergo this test.
  • Standard transthoracic echocardiography may not produce accurate results in obese people or those who have thick chests, chronic obstructive pulmonary disease, or chest wall abnormalities. For such patients, transesophageal echocardiography or a cardiac nuclear scan may be a better option.

Before the Stress Echocardiography

  • Antianginal drugs (such as nitroglycerin, beta-blockers, and calcium channel blockers) can affect test results by increasing your exercise tolerance. Your doctor may ask you to discontinue these medications for 1 or 2 days before the test.
  • Do not eat, drink, or smoke for 2 hours before the test.
  • Wear comfortable shoes and loose, lightweight clothing.
  • Immediately before the test, you will be asked to disrobe above the waist. (Women may wear a loose-fitting hospital gown that opens in the front.)

What You Experience

  • After you lie down on an examination table, ECG leads are applied to your chest to monitor your heart rate and rhythm during the test.
  • A water-soluble gel is applied to your chest to permit better transmission of the sound waves. The examiner then moves the transducer across your chest to obtain images of your heart while at rest.
  • For an exercise stress test, you begin by walking on a treadmill or pedaling a stationary bicycle. The pedaling tension on the cycle or the speed and grade of the incline on the treadmill are gradually increased until you reach a target heart rate set by your doctor.
  • For a dobutamine stress test, an intravenous (IV) line is inserted into a vein in your arm. The doctor infuses the drug and gradually increases the dose to mimic the effects of intensifying exercise. Another drug called atropine is sometimes needed to further increase your heart rate to the desired level.
  • The examiner obtains additional images of the heart at various stages of stress testing and at the end of the procedure.
  • The test concludes when you achieve an adequate heart rate or develop significant symptoms, such as angina or fatigue.
  • The test takes 20 to 60 minutes.

Risks and Complications

  • Although generally safe, this procedure carries a small amount of risk. Rare complications include severe angina, heart attack, abnormal heart rhythms, a drop in blood pressure, and fainting.
  • Dobutamine may cause flushing, palpitations, headache, and nausea, but these effects usually resolve quickly once the infusion is stopped.
  • Atropine can cause dry mouth and dilatation of the pupils, which may persist for an hour or so after the test.

After the Stress Echocardiography

  • You will rest until your blood pressure, heart rate, and other vital signs return to normal. The ECG leads and conductive gel are then removed from your chest.
  • If you received dobutamine, the IV line is removed from your arm and pressure is applied to the infusion site for several minutes. Blood may collect and clot under the skin (hematoma) at the infusion site; this is harmless and will resolve on its own. For a large hematoma that causes swelling and discomfort, apply ice initially; after 24 hours, use warm, moist compresses to help dissolve the clotted blood.
  • If there are no complications, you may resume your normal activities.

Results

  • A physician will examine the recorded images and video for evidence of any cardiac abnormality.
  • If a definitive diagnosis can be made based on this test, treatment will be started with diet, exercise, or medication.
  • In some cases, more invasive tests, such as cardiac catheterization, may be needed to further evaluate abnormal

Source:

The Johns Hopkins Consumer Guide to Medical Tests

Simeon Margolis, M.D., Ph.D., Medical Editor

Updated by Remedy Health Media

Publication Review By: the Editorial Staff at Healthcommunities.com

Published: 24 Jan 2012

Last Modified: 24 Jan 2012