Spring 2012 - Nuclear Stress Test
A scary name for a not-so-scary test
Some of the names of medical conditions and tests can conjure unpleasant, even frightening images in our minds. Nuclear stress testing is one of them. The word “nuclear” certainly has its share of negative connotations. But when used in studies of the heart, it can be a true lifesaver.
Cardiologists use nuclear stress testing to see how well blood is flowing through the heart’s blood vessels, known as coronary arteries, while patients are at rest and while their heart is working harder as it does during cardiovascular exercise. Nuclear stress testing can also help cardiologists judge:
- The size of the heart’s chambers
- How well the heart is pumping blood
- If the heart is damaged from blocked arteries
What makes the test “nuclear”?
The radioactive imaging agent makes the test "nuclear" Before testing begins, an IV is placed in the patient’s arm. A radioactive imaging agent is injected, but the imaging agent is not harmful. It travels within the bloodstream. Once it makes its way into the heart, clinicians use a gamma-ray camera to see whether the heart has any blocked arteries or if any damage has resulted from an occluded blood vessel.
The first part of the test is the “at rest” phase. The patient lies on their back while the camera moves around them for about 15 minutes. Next, a technologist places electrodes on the patient’s chest and a blood pressure cuff on the patient’s arm. The patient is then asked to walk on a treadmill.
If a patient cannot walk on a treadmill, clinicians will administer a medication that will stress the heart like cardiovascular exercise doesr. Lexiscan, adenosine and dobutamine are names of some of these medications. They are administered by IV.
Once the peak exercise level is reached, the patient receives another dose of the radioactive imaging agent through their IV. Approximately one hour later, another camera scan will be performed. Cardiologists can use longer-lasting radioactive agents such as thallium and do scans up to 24 hours later if the patient’s clinical condition warrants it.