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Nuclear Stress Test - Test Procedure

How do I prepare for a nuclear stress test?

You should not smoke, eat, or drink anything for about four to six hours before the test. You may be asked to avoid caffeine for up to 24 hours before the test. If you have diabetes, you should discuss dietary concerns for the day of the test with your healthcare provider to moderate your blood sugar levels. Talk to your doctor about any medications or dietary supplements that you are taking because they may affect the accuracy of the test. You may have to stop taking or reduce the dosage of certain medications before the test. You may be unable to resume taking some medications until the tracer is cleared from your body (about 24 hours). You should wear comfortable, loose clothing and shoes appropriate for exercising.

What does a nuclear stress test entail?

You will strip from the waist up (you can keep your bra on) and put on a hospital gown. You will be hooked up to an ECG so that your heart rate can be monitored—small sticky patches with wires attached will be taped to your body. The ECG also allows the technician to time the pictures for when the heart is moving the least; this reduces the chances of blurred images. To determine your target heart rate, the nurse will note your age, height, weight, and what medications you currently take. Depending on where the test is performed, the next step may vary. You will wear a blood pressure cuff for the exercise portion (running or walking on a treadmill). The exercise part may be done first, then the radioactive tracer is injected and pictures are taken. You may feel the needle prick when the intravenous (IV) line is inserted into your arm to administer the radioactive material. You will lie on the scanner bed with your arms overhead and a large camera will rotate 180º around you while taking multiple pictures. You must hold still when the pictures are taken to reduce the likelihood of blurring. After a few hours when your heart rate is back to normal, additional pictures are taken.

In one widely used test method, a radioactive tracer (usually thallium) is injected, and images are taken about 10 minutes later. You then exercise on a treadmill until you reach your predetermined target heart rate or until you ask to stop because of fatigue or pain. If you are unable to exercise, you will undergo a chemical stress test where a drug will be given to mimic the effects of exercise on the heart. When you reach your target heart rate with either chemical or exercise stress, a small amount of a different radioactive tracer (usually sestamibi) is injected. Fifteen to 30 minutes later, more pictures are taken. The first pictures taken show how blood flows to the heart during rest. The second set shows how the heart performs during exertion. Areas of the heart with normal blood flow appear light. Areas with reduced blood flow (indicating a blockage) absorb less of the tracer and appear dark.

How long does a nuclear stress test last?

The duration of the test will vary because of the different methods used. You should speak to your healthcare provider to find out how long your particular test will take. In most cases, it will take at least a few hours. At some facilities, the exercise portion and resting portion may be performed on different days.

What happens after a nuclear stress test?

After the test, you can eat, drink, and resume normal activities. You should drink plenty of fluids to flush the tracer from your body. If you don’t exercise regularly, you may experience chest pain, tiredness, muscle aches, and shortness of breath afterwards. If you had a chemical stress test, you may experience some minor side effects from the medication including nausea, heart palpitations, numbness in the arms or legs, flushing, chest pain, or headaches. A preliminary report may be available right after the test, but the complete results will not be ready for a day or more.


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