What is Nuclear Stress Test?
A nuclear stress test, also called a myocardial perfusion scan, evaluates blood flow to your heart muscle during rest and stress using a small amount of radioactive tracer injected into your bloodstream. The tracer, which is safe and causes no side effects for most people, travels through your bloodstream and is absorbed by healthy heart muscle. A special camera then takes images showing how well blood reaches different areas of your heart. By comparing images taken when your heart is at rest with images taken when it's working hard (during exercise or medication-induced stress), your doctor can identify areas that aren't receiving adequate blood flow.
Why is it Performed?
Your cardiologist may order a nuclear stress test if you're experiencing chest pain, shortness of breath, or other symptoms suggesting coronary artery disease. The test is more detailed than a standard stress test and can show not just whether you have blockages, but also where they're located and how severe they are. It helps determine if you've had a heart attack, assesses the effectiveness of treatments like angioplasty or bypass surgery, and helps your doctor develop a safe exercise plan. The test is particularly useful for patients who cannot exercise adequately on a treadmill, as medication can be used instead to stress the heart.
What to Expect
The nuclear stress test is performed in two parts over several hours. First, you'll receive a small injection of radioactive tracer through an IV, then wait 30-60 minutes while it circulates through your body. You'll lie under a special camera that takes images of your heart at rest. Next comes the stress portion: you'll either exercise on a treadmill or receive medication through your IV to increase your heart rate. At peak stress, you'll receive a second tracer injection. After another brief waiting period, more images are taken. The entire process typically takes 3-4 hours, though much of that time is spent waiting between imaging sessions. You can usually bring a book or device to help pass the time. The radioactive tracer leaves your body naturally within a couple of days.
Preparing for Your Test
Don't eat or drink anything except water for at least four hours before your test. Avoid all caffeine for 24 hours beforehand, including coffee, tea, chocolate, and certain medications, as caffeine can interfere with test results. Your doctor may ask you to stop taking certain heart medications before the test. Wear comfortable clothing and walking shoes. If you have diabetes, ask your doctor for specific instructions about medications and eating, as fasting can affect blood sugar levels. Inform your doctor if you're pregnant or breastfeeding, as nuclear imaging is not recommended in these situations.
Understanding Your Results
Your cardiologist will compare the rest and stress images to evaluate blood flow patterns. Normal results show uniform tracer distribution throughout your heart muscle during both rest and stress, indicating adequate blood flow to all areas. Abnormal results appear as darker areas on the images, suggesting reduced blood flow. Areas that look dark during stress but normal at rest indicate blockages that only cause problems during exertion. Areas that appear dark in both rest and stress images may indicate previous heart attack damage. Based on your results, your doctor will recommend appropriate treatment, which might include lifestyle changes, medications, or procedures like cardiac catheterization.
Have questions about Nuclear Stress Tests? Our experienced cardiology team is here to help. Contact Advanced Cardiovascular Specialists & Primary Care at (203) 334-2100 to schedule your appointment or discuss any concerns.
