What to Expect During a Nuclear Stress Test

Nuclear stress tests are necessary when a standard cardiac stress test cannot determine the cause of symptoms like chest pain or shortness of breath. In some cases, doctors use nuclear stress tests to guide treatments for certain heart conditions. Performing this test allows health professionals to determine how well the heart works, how large it is, what treatment is necessary, and what to expect in terms of future heart problems.

Doctors provide a specific list of rules that a patient must follow to prepare for a nuclear stress test. These requirements usually include avoiding caffeine, smoking, eating, and drinking for a certain period before the test. Some people may need to temporarily pause their medication schedules. Patients should not wear lotions, creams, or other body products on the day of the test.

Before starting the test, a technician inserts an IV line into the participant and injects a radiotracer. It takes 20 to 40 minutes for a person’s body to absorb the radiotracer. Experts then use medical imaging to record the body at rest. At this point, a nurse or technician will attach electrodes and a blood pressure cuff.

The test begins with the participant walking on a treadmill or riding a stationary bike. As the test progresses, the exercise becomes more difficult. Once the participant’s heart rate reaches a certain point or they develop symptoms, the test ends. People who cannot exercise will receive an injection that simulates the effects of exercise. When the heart rate peaks, a technician will inject more radiotracer and take more images.

After the participant finishes exercising, a doctor will typically allow them to rest before asking them to lie down. While the heart rate and breathing return to normal, technicians will watch for any issues. The radiotracer will leave the body naturally through urine or stool. The test taker should drink plenty of fluids to help flush the dye out of their system.

A healthy person will feel the same performing a nuclear stress test as they would during intensive exercise. The radiotracer itself can feel warm and may cause headaches or nausea. Underlying conditions may cause some individuals to feel chest pain, fatigue, muscle cramps, and shortness of breath during the test. Rarely, test participants experience dizziness, lightheadedness, and palpitations.

In some cases, test results qualify as healthy if the test participant was able to exercise as long or longer than the average for their age and sex. For others, healthy test results are those showing no dangerous increases in blood pressure, paired with ECG and imaging results that reveal no issues. These results may also reveal that nothing is affecting the blood flow through the coronary arteries.

A nuclear stress test may reveal a few issues. Nuclear stress tests often indicate reduced blood flow to the heart, often due to narrowing or blockage of one or more arteries. The medical imaging may show scarring of the heart muscle due to a previous heart attack. Depending on the results, doctors will form a treatment plan to manage the revealed condition.

While nuclear stress tests are usually safe, there are a few potential risks. Heart arrhythmias are among the most common complications. Reduced blood flow to the heart can cause significant chest pain during the test. Some people experience breathing issues or asthma-like symptoms. Extreme swings in blood pressure are also possible, as is a reaction to the radioactive tracer used during the test, although the latter is rare.

A nuclear stress test usually takes two to three hours, while the actual exercise portion lasts around 10 minutes. Organs and other structures within the body can produce false results, requiring special accommodations or a second test. Some people require additional tests, such as cardiac catheterization, based on their results.