Test Details & Preparation
A thallium stress test is a nuclear imaging test that shows how well blood flows into the heart during exercise and at rest. A radioisotope (nuclear material) is administered intravenously. It settles into the heart muscle and pinpoints spots that are abnormal.
Your doctor may order a thallium stress test if he or she suspects your heart is not getting enough blood flow (oxygen) when it’s under stress such as 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 or not a procedure or surgery was successful and to determine if your heart is healthy enough to start an exercise program.
The thallium stress test can show the size of the heart chambers how effectively the heart pumps how well the coronary arteries supply the heart with blood or if there is damage or scarring of the heart muscle from previous heart attacks.
The thallium stress test is usually performed at a hospital, medical centre or doctor’s office. A nurse or health care professional will insert an intravenous line (IV) usually on the inside of the elbow. A radioisotope or radiopharmaceutical medication called thallium is injected through the IV. You will then lie down for 15 to 45 minutes while the medication settles in the heart.
A special nuclear camera is used to take pictures of your heart, projecting them onto a computer screen. The doctor can then analyze these images to evaluate how weak or strong your blood flows to the heart.
You will likely fast after midnight the night before your test. Wear comfortable clothes and shoes for exercising. Twenty-four hours before the test, you will need to avoid all caffeine, including tea, soda and coffee, chocolate, and pain relievers that contain caffeine.
Your doctor will need to know all medications that you are taking. This is because some, like asthma medications, interfere with test results. Your doctor will also want to know if you’ve taken any erectile dysfunction medication including Viagra, Cialis, or Levitra 24 hours before the test.
Results depend on the reason for the test, how old you are, your history of heart problems and other medical issues. A normal result means blood flowing through the coronary arteries in the heart is normal. Abnormal results may indicate reduced blood flow to part of the heart scarring of the heart muscle due to a previous heart attack coronary artery disease or a too-large heart.