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Taking a Thallium Stress Test Personal Experience

Taking a Chemical/Thallium Heart Stress Test

Any patient who is asked to take a serious medical test is instantly concerned. Not knowing what the experience will be like is the biggest problem. We tend to fear the unknown. Such is the case when you go to a cardiologist and he suggests you have a chemical thallium heart stress test.

Having just completed my fourth chemical stress test over the last 10 or so years, I remembered the angst and trepidation I felt just because it sounded more serious and intimidating than a regular treadmill test. Doctors and nurses do a good job in explaining the procedures, but frequently, we want to hear from someone who’s taken the test, what the procedures are and how the patient felt during the process.

This is from a patient’s prospective, not a doctor’s so it will focus more on what the patient should expect to experience and not on the medical nomenclature or jargon. That information should be obtained from a heart professional.

The first questions are: What’s the difference between a chemical thallium treadmill test and a regular treadmill and why a thallium test? Usually it’s very simple. A patient may have a variety of reasons for being unable to get on or use a regular “exercise” type treadmill. Those reasons may be age and inability to walk safely on a treadmill or physical deformities that preclude walking at a rapid pace on a treadmill. In my case, I have an equilibrium problem that causes severe nausea and vomiting so a treadmill is not an option for me. So instead of a using a treadmill, a chemical is used to get the heart beating at a rate sufficient to measure using a scanner and monitoring.

The good news is that thallium provides that opportunity for the doctor to get important results similar to a regular treadmill test for those who can’t take one. It is not, a more or less serious test than a regular treadmill test, just a different option when necessary.

During the chemical part of the stress part of the test either dipyridamole (di-pi-RID’ah-mol) or adenosine are injected through an IV placed in your arm. The chemicals makes the blood vessels in and close to the heart, dilate, causing it to pump harder to maintain blood pressure. Doctors can see how the heart responds to this stress by the scans and measurements. The thallium test allows the doctor to get the similar results to study blood flow in the heart, examine damage done as the result of a heart attack, determine the benefits of procedures taken to improve circulation, determine the causes of angina or chest pain and establish a level of exercise a patient can safely perform

Important Note: Make sure you bring a lunch or something to eat. You’ll be asked to eat after the stress portion of the test. You’ll be reminded to bring something…make sure you do since you’ll have been fasting for a while.

What happens to a heart patient asked to take thallium Stress test?

1. You’ll receive a sheet from your doctor or hospital outlining what you are to do starting forty-eight hours before the test.

2. You’ll receive a time and date for the test. The test usually lasts from three to four hours.

3. You are not allowed to eat or drink anything four hours prior to the test.

4. On the sheet you’ll be instructed to quit using certain drugs that may distort the test for a certain period of time prior to the test. Follow your doctor’s instructions carefully.

5. You’ll be asked not to consume certain foods, particularly foods with caffeine, including chocolate, usually within twenty-four hours prior to the test.

6. You’ll be asked to make a list of all the medications you are taking to hand in when you arrive.

7. After the normal weighing and blood pressure check, an IV will be inserted into a blood vessel. You’ll also have lead stickers attached to your skin at critical locations on your chest and around your heart…similar to getting an Electrocardiogram (EKG).

8. The thallium will then be injected through the IV into your system. Technicians usually allow about thirty minutes for the thallium to circulate through your body before scanning. It is a nuclear dye, so to speak, so a scan of your pumping heart can be taken. This is prior to the test, and is designed to give the doctor a comparative view of the heart before and after.

9. After about thirty minutes you’ll be called in for a scan now that the thallium is distributed through your body. You’ll lie down and be asked to be perfectly still for about 12minutes while the scan takes pictures. The technicians will insist you lie absolutely still during scanning.

10. Sometime after the scan, you’ll be asked to remove your top and the technician will attach the electrodes or leads to the stickers.

11. Once everything is ready, the technician begins continuous injection of either dipyridamole (di-pi-RID’ah-mol) or adenosine which causes the heart to beat faster as the blood vessels around the heart dilate. The heart attempts to maintain blood pressure thus the faster beating response.

12. You’ll immediately begin to experience the sensation that you’ve been running which continues for the duration of the stress portion.

13. In about 30 seconds you’ll become flushed and feel like you’ve exercised vigorously. It is a strange feeling because you have not moved. Usually you’re asked to stay in a sitting position on the examining table.

14. At about two and a half minutes you’ll be feeling pretty stressed and the technician says “Thirty seconds to go,” and you’ll realize that you can make it another thirty seconds and the anxiety that the drug causes begins to subside.

15. The total length of time for the stress portion of the test is 3 minutes. I had excellent technicians. They’ll usually talk to you as the process move forward and it helps distract you and makes the time go quickly. They also usually tell you the time as it elapses.

16. The injection is then stopped and you immediately begin to feel better or more normal. I had no side effects from the four tests I’ve taken. Obviously, not all tests are the same. I held my mother’s hand as she went through the process at 87 year-of age. It was somewhat more stressful on her because of her age, but she came through it fine.

17. This is where bringing that lunch comes in. You are asked to return to the waiting room and eat. I have to say, that a tuna sandwich tastes mighty good about that time.

18. In about 20 to 30 minutes you’re asked to come back into the scanner room and go through the scanning procedure again. You’re asked to lie still for 12 minutes as the scanner takes its pictures.


Again, a chemical/thallium type test is no different from a regular treadmill test, just a different method of getting the heart pumping. Other than making sure you take a good lunch, preferably one of your favorites, my personal suggestion during the stress portion of the test, is try to relax your mind and have a “can do” attitude. I think it helps.

Two caveats:

(1) Each doctor or hospital may have their own specific preferences that may differ somewhat from my experience, but generally speaking, you should find the procedures are similar for most medical facilities in the U.S.

(2) There are different types of chemical stimulants that a doctor may use which could require different processes depending on your doctor’s choice.