What does a negative (normal) nuclear stress test indicate?
Women with a negative (normal) nuclear stress test have a low risk of developing future heart problems including heart attack. In women who have been diagnosed with heart disease, a normal nuclear stress test suggests a less than 1% annual risk of dying or having a heart attack.1-3 Women with diabetes and a normal nuclear stress test have a low risk of heart problems in the next 2 years, but their risk may rise sharply after that so they should have a follow-up test sooner than a woman without diabetes.4
What does a positive (abnormal) nuclear stress test indicate?
The tests can be mildly, moderately, or severely abnormal. The risks of future problems increase with each category. Some but not all studies suggest that women with a positive (abnormal) test have a higher risk of dying or having a heart attack than men with an abnormal test, particularly when the test is severely abnormal.5-7 Your healthcare provider will discuss the results with you and prescribe further tests or treatments.
If you had nuclear stress test that involved exercise, your fitness level and response to exercise can tell a lot about your risk for future heart problems; see Exercise ECG for details.
Are nuclear stress tests accurate?
Images may be blurred in women who are obese, have smaller hearts, or large breasts. If you are obese or have large breasts, the extra tissue may muffle the radioactive energy of the tracer, making it appear that it is not being absorbed as well. This could cause a false positive result—the test indicates a problem but in reality there is none. Modern nuclear stress tests include computer programs that correct for some of this blurring and muffling. In addition, timing the pictures for when the heart is moving the least ( ECG-gating) improves the quality of the nuclear stress test image. When these techniques are used, nuclear stress testing has a similar accuracy in men and women.8 Of the radioactive tracers used, thallium is less accurate in women than sestamibi because it is more likely to be muffled by breast tissue.9