The heart receives life-giving blood from vessels called coronary arteries. If these arteries become partially blocked or narrowed by the accumulation of fatty materials, the heart may not receive the blood it needs to function properly. This narrowing of coronary arteries is called coronary atherosclerosis or, more commonly, coronary artery disease (CAD).
As CAD progresses, the heart muscle may not receive enough blood when under stress (for example, when exercising). This often results in chest pain called angina pectoris. On the other hand, there may be no outward physical signs of the disease. If CAD is limiting blood flow to a part of your heart, the nuclear stress exam may be useful in detecting the presence and significance of CAD. This test will take one and one half to three hours to complete.
There are three types of procedures that can be used for this test. Your cardiologist will determine which one you should take.
Precautionary Information
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Nuclear Treadmill Stress Test
The tracer administered during this stress exam contains a small amount of radioactivity. The amount of radiation you will be exposed to is comparable to that from an x-ray CAT (CT) scan. You will be given this tracer before and during your stress test. Adverse patient reaction to the tracer is rare. You may briefly notice a metallic taste a few seconds after injection has occurred. Other side effects have rarely occurred.
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Nuclear Adenosine Stress Test (chemical stress test)
Intravenous Adenosine and LexiScan are drugs designed to dilate your blood vessels and may cause some side effects. In most cases, these effects may subside quickly or be easily reversed. Some of these effects may be experienced during or immediately after the test, including chest pain, headache, dizziness, changes in heart rate and blood pressure, nausea and flushing. You will be given the tracer before and during your stress test.
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Nuclear Dobutamine Stress Test (chemical stress test)
I.V. Dobutamine is used for asthma patients and is a drug designed to increase the heart rate. Side effects which may occur include chest pain, headache, dizziness, changes in heart rate and blood pressure, nausea and flushing, heart pounding and jitteriness. You will be given the tracer before and during your stress test.
What Should I Do Before the Test?
- You will be asked to refrain from eating or drinking 4 to 6 hours prior to the test. This will minimize the possibility of nausea, which may accompany vigorous exercise after eating. In addition, the pictures of your heart are clearer when the stomach is not full.
- Your cardiologist may decide to temporarily discontinue certain heart/blood pressure medications prior to the stress exam. These are discontinued because some heart medications may interfere with the accuracy and effectiveness of the exam.
- A hospital gown may be provided on the day of the test. Sweat pants or shorts are preferred for the exercise portion of the exam (loose, comfortable clothing). You should wear comfortable footwear appropriate for brisk exercise on a treadmill (a moving belt you walk on). You will work hard during the test and comfortable clothing will make it easier for you.
