ECG Stress Test or Exercise Stress Test
In cardiac stress test, the electrical activity of the heart is monitored with ECG leads while you exercise on a stationary bicycle or treadmill. Abnormal ECG tracings during the test may indicate the presence of coronary artery disease or other cardiac abnormalities.
Purpose of the Cardiac Stress Test
- To detect inadequate flow of blood (ischemia) to the heart muscle and 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 identify abnormal heart rhythms (or arrhythmias) that develop during physical exercise
- To assess the effectiveness of various drugs to treat arrhythmias or angina
- To evaluate the heart prior to major surgery
- To detect coronary heart disease in asymptomatic high-risk people
- To develop a plan for rehabilitation after a heart attack, including pace and intensity of the rehabilitation
Who Performs Cardiac Stress Test
- A doctor with a nurse or technician
Special Concerns about Cardiac Stress Test
- People who are unable to exercise adequately because of orthopedic, arthritic, or lung disorders may instead be given dobutamine, a drug that mimics the effects of exercise by increasing the rate and strength of the heart’s contractions.
- Certain medical conditions may affect test results, including high blood pressure, valvular heart disease, left ventricular hypertrophy, severe anemia, and chronic lung disease.
- This test cannot diagnose cardiac ischemia in people with left bundle branch block (an abnormal heart rhythm); these patients may undergo an alternative test, such as a cardiac nuclear scan with a dobutamine stress test.
- Because this test places significant stress on the heart, it may not be appropriate for people with unstable angina, uncontrolled hypertension, severe aortic valvular heart disease, severe congestive heart failure, or uncontrolled arrhythmias.
Before the Cardiac Stress Test
- 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.
- The doctor will take your blood pressure and pulse.
- Do not eat, drink, or smoke for 4 hours before the test.
- Wear comfortable shoes and loose, lightweight clothing.
- At the testing facility, you will be instructed to disrobe above the waist. (Women may wear a loose-fitting hospital gown that opens in the front.)
What You Experience
- ECG leads are applied to your chest to monitor your heart rate and rhythm during the test. Pretest measurements of your heart rate and blood pressure are taken before you begin exercising.
- 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 test concludes when you achieve an adequate heart rate or develop significant symptoms, such as angina or fatigue.
- The test takes about 20 minutes.
Risks and Complications of Cardiac Stress Test
- Although generally safe, this test carries a small amount of risk. Rare complications include severe angina, heart attack, arrhythmias, 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 Cardiac Stress Test
- You will rest until your blood pressure, heart rate, and other vital signs return to normal. The ECG leads 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 of Cardiac Stress Test
- The doctor analyzes the ECG tracings for signs of coronary ischemia and also evaluates your performance and symptoms during the test.
- If a definitive diagnosis can be made based on these findings, treatment will be started with diet, exercise, and/or medication.
- In some cases, more invasive tests, such as cardiac catheterization, may be needed to further evaluate abnormal results.
The Johns Hopkins Consumer Guide to Medical Tests
Simeon Margolis, M.D., Ph.D., Medical Editor
Updated by Remedy Health Media