Nuclear stress tests evaluate the condition of the heart under strain. A doctor may recommend a nuclear stress test for a number of reasons, including:
Diagnosing Coronary Artery Disease
A nuclear test can help doctors determine if a patient's symptoms, such as shortness of breath or chest pains, are related to the artery damage or disease caused by the buildup of plaque.
Examine the Size and Shape of the Heart
A nuclear test provides doctors with an opportunity to see if a patient's heart is enlarged. Doctors can also measure how well the heart is pumping blood.
Treat Heart Conditions
Patients suffering from a number of heart conditions, including arrhythmia, can discover how well treatments are working based on the results of a nuclear stress test.
A nuclear stress test is similar to a stress echo test in that patients can expect to have two sets of images taken of the heart, once during physical exertion, either while exercising on a treadmill or stationary bike, and another set about two hours later when the body is at rest. However, there are differences between the two types of stress tests.
During a regular stress echo test, patients who are unable to exercise are given dobutamine, a drug that increases the heart rate without exercise. However, patients who cannot exercise and also cannot take dobutamine because of an arrhythmia (irregular heartbeat) will need to take a nuclear stress test, which uses the drug adenosine instead.
Also, while a stress echo uses an ultrasound to produce images of the heart, a nuclear stress echo uses a radioactive dye that is injected into the bloodstream. A special scanner that detects the radioactive material takes pictures of the heart. Light spots on the images indicate that not enough radioactive material is getting to the heart – evidence that there is inadequate blood flow going to the muscle. The images can also highlight areas of heart damage.
While at times the nuclear stress test offers a clearer image, the procedure takes longer than a traditional stress test, and results aren't immediately available because they must be processed by a technician before the cardiologist can view them.