Overview of a thallium stress test
A thallium stress test is a nuclear imaging test that shows how well blood flows into your heart while you’re exercising or at rest. This test is also called a cardiac or nuclear stress test.
During the procedure, a liquid with a small amount of radioactivity called a radioisotope is administered into one of your veins. The radioisotope will flow through your bloodstream and end up in your heart. Once the radiation is in your heart, a special camera called a gamma camera can detect the radiation and reveal any issues your heart muscle is having.
Your physician may order a thallium test for a variety of reasons, including:
- If they suspicious your heart isn’t getting enough blood flow when it’s under stress – for example when you exercise.
- If you have chest pain or worsening angina.
- If you’ve had a previous heart attack.
- To check how well medications are working
- To determine whether a procedure or surgery was fruitful.
- To determine whether your heart is healthy enough to start an exercise program.
The thallium stress test can show:
- The size of your heart chambers.
- How effectively your heart pumps that is, its ventricular purpose.
- How well your coronary arteries supply your heart with blood, recognized as myocardial perfusion.
- If your heart muscle is damaged or damaged from previous heart attacks.
How is a thallium stress test performed?
The test must be done at a hospital, medical centre, or doctor’s office. A nurse or healthcare professional inserts an intravenous (IV) line, usually on the inside of your elbow. A radioisotope or radiopharmaceutical medication, such as thallium or sestamibi, is injected through the IV.
The radioactive material marks your blood flow and is picked up by the gamma camera.
The test includes an exercise and resting portion, and your heart is photographed during both. The doctor administering your test will determine the order that these tests are performed in. You’ll receive an injection of the medication before each portion.
During the thallium stress test, you lie down for 15 to 45 minutes while the radioactive physical works its way through your body to your heart. You then lie down on an examination table with your arms above your head.
In the exercise portion of the test, you walk on a routine or pedal an exercise bicycle. Most likely, your doctor will ask you to start slowly and progressively pick up the pace into a jog. You may need to run on an incline to make it more challenging.
If you’re unable to exercise, your doctor will give you a medication that stimulates your heart and makes it beat faster. This simulates how your heart would act in exercise.
Your blood pressure and heart rhythm are monitored while you exercise. Once your heart is working as hard as it can, you’ll get off the treadmill. After about 30 minutes, you’ll lie down on an exam table again.
Risks and complications of a thallium stress test
Most people stand the thallium stress test very well. You may feel a sting when the exercise simulating medicine is injected, followed by a sensation of heat. Some people may experience a headache, nausea, and a racing heart.
The radioactive material will permission your body through your urine. Complications from radioactive material vaccinated into your body are very rare.
Rare complications from the test can include:
- Arrhythmia or irregular heartbeat
- Increased angina or pain from poor blood flow to the heart
- Laboured breathing
- Asthma-like symptoms
- Large changes in blood pressure
- Skin rash
- Difficulty breathing
- Chest discomfort
- Palpitations or irregular heartbeat
Why is a thallium stress test required?
Thallium stress test gives the physician the same information as the standard treadmill stress test, it also provides the following information:
- The areas of the heart lacking adequate blood and oxygen.
- If the patient has had a heart attack in the past and the area of the heart where the heart attack occurred.
Thallium stress test procedure
This procedure is also called the Myocardial Perfusion Imaging test since this involves imaging and testing the perfusion (flow) of blood through the heart. The preparation for the test involves:
- A thorough consultation with your physician regarding your medical history, allergies, the possibility of pregnancy, smoking or drinking habits, and exercise habits.
- Checking whether and in what dose should you be taking your heart, diabetes or any other ongoing medicines.
- Wear loose, comfortable clothing and shoes for exercise.
During the myocardial perfusion imaging (MPI) procedure, you will be given a radioactive dye, called a tracer or radiotracer, through an IV. Then, you will be asked to rest for 20 to 30 minutes, during which time the dye will travel to your heart. Then the first set of images will be taken with the help of a “gamma” camera, while you are at rest.
After this, a nurse will place electrodes on your body and a cuff to monitor your blood pressure to proceed with the myocardial perfusion imaging stress test. Then, you will be asked to exercise on a treadmill or stationary bike, while your heart rate and blood pressure will be monitored. Once your heart rate reaches a target, set before preliminary the thallium cardiac stress test, or you feel severe discomfort.
Although it is a fairly safe procedure, there may be some side effects or risks of the thallium cardiac stress test, such as:
- Radioactive dye allergy
- High or low blood pressure during exercise.
- Moderate or major heart pain
- Dizziness or fainting