Exercise Stress Echo
This is a test of heart function by making the heart exercise, typically on
a motorised treadmill accompanied by monitoring of your heart rate, blood pressure, ECG tracings . Speed and slope gradually increase every three minutes, but the level of exercise is usually no more strenuous
than a brisk walk.
In contrast to a standard exercise treadmill test, this is now coupled with direct images of heart contractility on Echo before starting the stress test and compared to images obtained post exercise.
Same arrangements as for an exercise treadmill test but with added echo images before and after to increase diagnostic accuracy.
How does Stress Echo work?
Patients with coronary artery blockages may have minimal or no symptoms during rest. However, symptoms and signs of heart disease may be unmasked by exposing the heart to the stress of exercise. During exercise, healthy coronary arteries dilate (develop a more open channel) than an artery with a blockage. This unequal dilation causes more blood to be delivered to heart muscle supplied by the normal artery. In contrast, narrowed arteries end up supplying reduced flow to it's area of distribution. This reduced flow causes the involved muscle to "starve" during exercise. The "starvation" may produce symptoms (like chest discomfort or inappropriate shortness of breath), ECG abnormalities and reduced movement of the heart muscle. The latter can be recognized by examining the movement of the walls of the left ventricle (the major pumping chamber of the heart) by Echocardiography.
Preparing for the Echo Stress Test: The following recommendations are "generic" for all types of cardiac stress tests:
Do not eat or drink for three hours prior to the procedure. This reduces the likelihood of nausea that may accompany strenuous exercise after a heavy meal. Diabetics, particularly those who use insulin, will need special instructions from the physician's office.
Specific heart medicines may need to be stopped one or two days prior to the test. Such instructions are generally provided when the test is scheduled.
Wear comfortable clothing and shoes that are suitable for exercise.
An explanation of the test is provided and the patient is asked to sign a consent form.
How long does the entire test take?
A patient should allow one and a half, to two hours for the entire test, including the preparation, echo imaging and stress test.
How safe is a Stress Echo test?
There are no known adverse effects from the ultrasound used during Echo imaging. The risk of the stress portion of the test is rare and similar to what you would expect from any strenuous form of exercise (jogging in your neighborhood, running up a flight of stairs, etc.).
As noted earlier, experienced medical staff are in attendance to manage the rare complications like sustained abnormal heart rhythm, unrelieved chest pain or even a heart attack. These problems could potentially have occurred if the same patient performed an equivalent level of exercise at home or on a jogging track.
What is the reliability of Stress Echo?
If a patient is able to achieve the target heart rate and if the Echo images are of good technical quality, a Stress Echo is capable of diagnosing important disease in more than 85% of patients with coronary artery disease. Also, it can exclude important disease in more than 90% of cases when the test is absolutely normal.
How quickly will I get the results and what will it mean?
The physician conducting the test will be able to give you the preliminary results before you leave the Stress Echo laboratory. The results of the test may help confirm or rule out a diagnosis of heart disease. In patients with known coronary artery disease (prior heart attack, known coronary blockages, previous treatment with angioplasty, stents or bypass surgery, etc.), the study will help confirm that the patient is in a stable state, or that a new blockage is developing.
The results may influence your physician's decision to change your treatment or recommend additional testing such as cardiac catheterization.