Instructions for cardiac procedures
Nuclear Stress Test
A Nuclear stress test is used to assess heart function. It can be used to measure how well your heart supplies blood to your body as well as to see if there are any areas where the heart muscle does not receive good blood flow either due to damage (myocardial infarction - MI) or temporary lack of oxygen at stress (ischemia). Nuclear stress tests are often performed for cardiac clearance prior to surgery.
Do not eat or drink for 6 to 8 hours before your appointment. It is best to stay without food after midnight on the night before your exam is scheduled. Also, do not eat or drink any caffeinated foods, beverages, supplements, or medications for 24 hours before your test. Caffeine can be found in coffee, tea, chocolate, certain soft drinks, as well as some cold and migraine medications. Decaffeinated products such as decaf coffee or soda still contain small amounts of caffeine and should be avoided before this exam.
Some medications can interfere with this exam. You should speak to your physician about what medicines you are taking and whether to stop any of them before your stress test. Since some of these medications take as long as 48 hours to clear out of your body, you should speak to your physician several days before your exam date. If you are unable to exercise on the treadmill, a medication will be administered in your vein to stress your heart. If you are undergoing this type of an exam (chemical stress), you may take your heart and blood pressure medications as instructed by your physician.
If you have diabetes, please speak to your physician prior to this exam to receive special instructions you may need regarding your medications. Wear comfortable clothes and rubber-soled shoes or sneakers for the treadmill portion of this exam. Please allow three to four hours for the entire test. You will receive two injections of a small amount of radioactive material. The level of radioactivity used is extremely low and has no side effects. An intravenous line (IV) will be placed in your arm prior to your first injection (thallium or Cardiolite) and will be re-used later for your second injection (Cardiolite and or stress agent).
About 30 minutes after your first injection, you will be placed under a gamma camera and pictures of your heart will be taken. This camera does not produce any radiation. It will be placed close to your chest and pictures will be taken for approximately 15 minutes. This portion of the test is called the rest study. After the rest study, our trained staff will place EKG leads on your chest. The EKG will be used to continuously monitor your heart during your stress test. Your oxygen saturation, heart rate and blood pressure will also be monitored.
Your heart will be stressed, either through exercise on a treadmill or through the use of medication (chemical stress). Before the end of the stress test, a second injection (Cardiolite) will be administered. This radiopharmaceutical is taken up by your heart muscle and can be visualized by the gamma camera just as in the rest study. Normal responses during testing include feeling tired, shortness of breath, chest pain or tightness, abdominal discomfort and sweating. You should tell our medical professionals if you feel any of these symptoms: chest, arm or jaw discomfort, severe shortness of breath, extreme tiredness, dizziness, lightheadedness, leg cramps or soreness. The test will be stopped if it is unsafe for you to continue.
When the stress portion of the test is over, you may eat or drink. About 30 minutes after the stress, you will be placed under the gamma camera and another set of pictures of your heart will be taken. These pictures will be processed and compared side by side with your initial pictures. This helps the radiologist to be able to determine if there is a difference in your heart muscles between when you are at rest and when you are stressed.
At the end of the procedure, you may resume all your medications. Your images will be reviewed by our nuclear cardiologist, and results will be sent to your physician. Your physician will discuss these results with you.
Nuclear stress test images showing perfusion to the cardiac muscle
Myocardial Viability Scan
Myocardial viability scan is used to assess the viability of heart muscles after a heart attack or myocardial infarction (MI). Your technologist will explain the test and answer any questions you may have. A small amount of a radioactive tracer will be injected into the vein, typically in the arm. Approximately 10 to 15 minutes after the injection, a set of images will be taken that show tracer distribution to the heart muscle. The images will be repeated four hours after tracer injection and compared side by side with the earlier images. This helps to evaluate the redistribution of the tracer in the heart muscles over time. These images will be reviewed by our nuclear cardiologist, and results will be sent to your physician. Your physician will discuss these results with you.
nuclear stress test slices showing the heart's pumping motion
A MUGA scan is used to check heart function without a stress test. It measures how well your heart is able to supply blood to your body, as well as how well your heart’s “pump” works. MUGA scans are useful for following up on known cases of chronic heart failure (CHF), cardiomyopathy, or chronic heart disease. It is also done pre- and post-chemotherapy to monitor effect of treatment on heart function.
When you arrive, the technologist will explain the procedure to you. Once in the exam room, you will be asked to lie on your back on the imaging table. The technologist will draw some blood from your vein and tag it with a radiotracer. The tagged blood is then re-injected through your vein. Images of your heart will be acquired while hooked up to an EKG monitor. Your images will be reviewed by our nuclear cardiologist and a report sent to your physician. Your physician will discuss these results with you.
The heart pumping during a heart beat