Stress echocardiography, also known as an echocardiography stress test or stress echo is a test that indicates the functioning of the heart and the blood vessels. This test uses ultrasound imaging to assess how efficiently the heart muscle is pumping blood in the body. It is very useful in determining the decrease in the flow of blood to the heart due to reasons such as narrowing or blocking of the coronary arteries. This test mainly evaluates how well the heart functions under stressful conditions. This stress could be triggered by exercising on a treadmill or through a medicine known as dobutamine. The medication is used in cases where the concerned person is unable to exercise; this medication imitates the effects of exercise on the heart.
However, in general cases, the test is performed while the patient is exercising on a treadmill or a stationary cycle. During this time, the doctor monitors the condition of the heart, including blood pressure and the rhythm. When the heart rate reaches its maximum, ultrasound images are used to evaluate if the heart muscles are receiving the required quantities of blood and oxygen, while exercising.
Purpose of the stress echocardiography test
A stress echocardiography test may be conducted in situations where the patient experiences chest pain which might be caused due to coronary artery diseases or in cases where a patient suffers myocardial infection (heart attack). The stress echocardiography test can also be used to determine the level and intensity of exercise that can be undertaken by a patient who is in cardiac rehabilitation. Additionally, the test is also used to assess the effectiveness of treatment, such as:
- Bypass grafting
- Anti-arrhythmic medicines
The test is very safe and non-invasive with minimum or no complications; some rare complications might include an abnormality in heart rhythm, dizziness, lack of consciousness or heart attack.
Procedure of the stress echocardiography test
The test takes about 45 to 60 minutes and can be conducted in the doctor’s office or at an echocardiography lab. It is a simple test with rare complications. Hence, to ensure there is no risk of problems in the test, the doctor might suggest a few measures to follow before the test, these include:
- No eating or drinking at least three to four hours prior to the test
- No smoking on the day of the test
- Check with the doctor before taking caffeine in any form
- Check with the doctor for all medications that you might be regularly taking; certain medications can hamper the results of the test and create complications; thus those might be avoided on the day of the test
- Wear running shoes and comfortable clothes.
Once that is taken care of the actual procedure of the stress echocardiography test begins. The test is divided into three stages, including:
Resting echocardiography: This is a critical step because this will help assess the functioning of the heart at rest and compare it with the functioning when stressed. In this step, the doctor first sticks small patches on the chest, known as electrodes which are connected to an ECG (Electrocardiograph) machine. This ECG machine evaluates the functioning of the electrical activity of the heart, more specifically, the heart rate and the regularity of heart rhythms. The doctor will also monitor your blood pressure during this time. Once this is done, the patient will be asked to lie on the side to go through resting echocardiography that will provide in-depth insight into the movement of the heart and health of internal structures, while resting. This will be done by applying a special gel to the skin and using a device called a transducer to emit sound waves and produce images.
Stress test: In this step, the doctor aims to increase or maximize the rate of your heart to record and analyse its functioning. The patient will be asked to exercise on a treadmill or a stationary cycle for 7-10 minutes or until the patient feels extremely tired. This will shoot the heart rate of the patient, helping in the assessment. During this time, ultrasound images of the heart muscles are taken to analyse the condition of the heart. The mode and intensity of exercise will depend on the patient’s condition; incase a person feels dizzy, weak or has pain in the chest – the doctor must be immediately informed.
Stress echocardiography: This test is conducted when the patient is asked to stop exercising because the heart rate has significantly risen, providing enough data for analysis. When the patient is asked to stop exercising, more ultrasound pictures of the heart are recorded till the time the heart rate, blood pressure return to normal. This helps to actually evaluate the working of the heart muscles under stressful conditions.
Results of the stress echocardiography test
A stress echocardiography test is simple and very useful to know if there are any problems with the heart’s functioning. The test is extremely reliable, and the results are simple to interpret. If the results of the stress echocardiography test are normal, it implies that the heart is healthy, it is receiving an adequate supply of blood and oxygen even in stressful conditions, and that there is no blockage or narrowing of the coronary arteries.
However, if the results of the stress echocardiography test are negative, the reasons can be intense and would need medical attention. Abnormal results indicate that the heart is devoid of essential nutrients, blood and oxygen during times of stress due to issues such as coronary artery diseases or a previous heart attack that has damaged the heart tissues.
This test is also very useful in determining if the current cardiac rehabilitation plan of the patient is working effectively. In case, the results indicate otherwise, a change in medications and treatment may be opted for.
In all, stress echocardiography is very useful in the early diagnosis of heart problems and risks of heart attacks. It is a simple, non-invasive and a very reliable test.