A stress echocardiogram is a diagnostic test used to evaluate the strength of the heart muscle as it pumps blood throughout the body. Using ultrasound imaging, the stress echocardiogram detects and records any decrease in blood flow to the heart caused by narrowing of the coronary arteries. The test, which takes place in a medical center or in the doctor's office, is administered in two parts: resting and with exercise. In both cases, the patient's blood pressure and heart rate are measured so that heart functioning at rest and during exercise can be compared. The ultrasound images enable the doctor to see whether any sections of the heart muscle are malfunctioning due to a poor supply of blood or oxygen.
Reasons for a Stress Echocardiogram
The test is administered to patients whose heart health is in question or to evaluate ongoing cardiac treatment. Patients are candidates for a stress echocardiogram if they have been having chest pains or angina or have recently had a heart attack. They may also have the test as a requirement prior to heart surgery or before beginning an exercise program. The stress echocardiogram measures:
- How well the heart muscle and valves are working
- How well the heart handles exercise (stress)
- Whether the patient is likely to have coronary artery disease
- Whether the patient's heart function has improved after treatment
- Whether chambers of the heart are enlarged
Results of the stress echocardiogram are helpful to the cardiologist in determining whether there is a problem with heart muscle strength and what that problem might be. They also help determine an appropriate new course of treatment or evaluate a previous one.
Preparing for a Stress Echocardiogram
Before undergoing a stress echocardiogram, patients should ask their doctors whether it is necessary to temporarily stop taking certain medications prior to the test, particularly medications prescribed for erectile dysfunction. Patients should refrain from eating or drinking for at least 3 hours before the test and wear comfortable, loose-fitting clothing to the procedure.
The Stress Echocardiogram Procedure
Before the test begins, electrodes are placed at various locations on the patient's body, including the chest, arms and legs, to record electrical activity in the heart. The patient will also wear a blood pressure cuff. The resting portion of the procedure is administered while the patient lies on the side with the left arm extended. The doctor moves an ultrasound transducer over the patient's chest. A special gel is applied to enable the transducer to move smoothly and to transmit sound waves directly to the heart.
During the second portion of the test, the patient exercises by walking on a treadmill or peddling on an exercise bicycle. At approximately 3 minute intervals, the patient is asked to speed up activity or to walk up an incline. Depending on the patient's age and fitness level, the test can take from 5 to 15 minutes. Normally, the test is stopped when the patient's heart is beating at a targeted rate, or when fatigue, chest pain, or blood pressure changes necessitate cessation. The test results provide the doctor with critical evidence as to whether the heart has more difficulty functioning under stress.
Some patients who require the stress echocardiogram may not be strong enough to perform the necessary exercise routine. In such cases, a drug is administered intravenously to make the heart beat faster and more strongly, simulating exercise. Most patients are relatively comfortable during this test, though some become very fatigued and unable to complete it. In rare instances, patients may experience one or more of the following symptoms during the stress echocardiogram procedure, including:
- Chest discomfort or pain
- Skipped or extra heartbeats
- Shortness of breath
It is important for patients to report any unusual sensations to the medical professional administering the test. If the test results are completely normal, no further treatment is necessary. If the test shows problems with the heart muscle or with coronary circulation, medications may have to be altered or the patients may require further testing or a surgical procedure.
Risks of a Stress Echocardiogram
There is a very low rate of risk associated with a stress echocardiogram since it is mostly non-invasive and the patient is carefully monitored during the entire procedure. Complications occur rarely, but may include heart arrhythmia, syncope (fainting), or heart attack.