A nuclear stress test is used to gather information about how well the coronary arteries provide blood flow to the heart muscle (myocardium) during physical activity and at rest. It also measures how well the heart muscle is pumping. The test usually involves taking two sets of images of the heart. One set is taken at rest , before exercising. A second set is taken following exercise on a treadmill or following an intravenous infusion of a medication that simulates the effects of exercising.
The test involves two injections of a small amount of a radioactive solution (radioisotope) to create the rest and exercise images. Special cameras outside of the body detect the radioisotope and use it to create pictures of the heart muscle. These images are compared and can show damage to the heart muscle such as after a heart attack and/or blood flow problems that may be a warning of a future heart attack.
A nuclear stress test may be given if a physician suspects coronary artery disease or another heart problem, or if an exercise stress test alone wasn't enough to pinpoint the cause of symptoms like chest pain or shortness of breath. It may also be recommended in order to guide the treatment for someone already diagnosed with a heart condition.
At the Cooper Heart Institute, we combine the expertise and experience of our physicians with advanced equipment and software to offer a full range of cardiac studies, including nuclear stress test.
What to expect
An intravenous (IV) line will be started in the hand or arm. An injection of the radioisotope is given through the IV, and the “rest” pictures of the study are taken.
Next, the technician or nurse will attach small sticky patches (electrodes) on the chest to monitor heart function throughout the exercise or IV infusion part of the test. A person may walk on a treadmill or receive a special IV medicine if they can’t exercise. The technician or nurse will continue to monitor the heart until the patient reaches their maximum exercise capacity or the infusion is completed. . A second “stress/exercise”dose of the radioisotope is injected. The patient will be observed to confirm that they have returned to their starting blood pressure and heart rate and are safe to leave the monitored testing area.
When finished exercising or receiving the IV infusion and the “stress” dose of the radioisotope, the patient will be asked to again lie very still under the camera. The camera will record images that show the amount of blood flow that reaches the heart muscle during exercise. These images will be compared to the first set.
The results of the nuclear stress test can help doctors determine if the heart muscle and coronary arteries are working properly while a person is at rest, compared to while exercising.