Also known as a thallium stress test, a nuclear stress test is used to measure blood flow into the heart. The test is particularly referred to as a stress test, because a person exercises during the test by walking on a treadmill, which measures the heart's ability to support the additional blood and oxygen needed while exercising. Because the test requires both the injection of a radioactive substance for imaging as well as causing the heart to support exercise activity, the test can involve some complications.
How It Works
Two parts exist to the nuclear stress test. The first requires a person to either walk on a treadmill or take a medicine known as a vascillodilator, which increases heart rate. Either approach helps to place the heart under stress, speeding up pulse rate and blood vessel dilation.
The second portion involves injecting a radioactive substance (typically thallium or sestamibi), then an imaging scan creates pictures of the substance moving through to the heart. Next, a person will lay or sit quietly for several hours, then take more imaging scans, which displays how blood moves through the body while it is at rest.
An arrhythmia is an abnormal heart rate that causes the heart to either beat too fast or too slowly. While there are many causes of an arrhythmia, such as chemistry imbalances or endocrine system abnormalities, the chief contributing factor when it comes to a nuclear stress test is due to the condition of your heart being compromised. Because the nuclear stress test involves placing extra strain on the heart, an arrhythmia may be heightened or more noticeable following a nuclear stress test.
Angina is a form of chest pain that occurs when the heart does not get enough blood pumped into the heart. When a stress test causes the heart to work harder, this can cause chest pain or pressure associated with angina to occur. This type of angina is known as stable angina, which is typically associated with exercise. While angina does not necessarily mean a person will have a heart attack, the chances of heart attack are heightened, according to the National Heart Lung and Blood Institute.
While the radiation dosage administered for nuclear stress tests is very low, according to radiologyinfo.org, it is possible for a person to have an allergic-type reaction to the nuclear dosage that can manifest itself through asthma-like symptoms or even a rash. The initial injection can cause pain and redness, which typically go away quickly.
Because of potential difficulties with breathing or other reactions to radiation, a person should always inform their physician if he has experienced previous reactions associated with radiation dosage.
Women also should take precautions to inform their physician if there is a possibility of pregnancy. If a woman is currently breastfeeding, she should speak with her physicians about safety precautions associated with the procedure.