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Treadmill (exercise) Nuclear Stress Test

 
What it tells us
Stress testing is used usually to determine if there is a problem with blood supply to an area of the heart (coronary artery blockage).

This test is more involved and gives more information (location, extent of blockages) than the EKG-only based standard treadmill exercise stress test. It is also more sensitive and specific (fewer false results) than the EKG-only based test.

Occasionally, this test is ordered for other reasons such as looking for heart rate, arrhythmias (irregular heartbeat), blood pressure or other responses to a higher heart load.
How long does it take?
Variable, usually a total of 2-3 hours. Very little of that time will be spent actually on the treadmill. Most of the test time is spent imaging the heart with cameras and allowing time for the injected materials to distribute in the body.
What to expect
An intravenous catheter will be placed, and you will be administered a very small dose of a nuclear agent (the amount of radiation is very safe). This will then distribute throughout the body, and a set of "rest" heart images will be taken with a special camera.

During imaging, you will be laying down on a table. The camera spins around your chest; however your head will not be in a confined area (for those that are claustrophobic). Imaging lasts approximately 20 minutes.

A second "distribution" time will then take place where you may be seated in the waiting area for 45 minutes.

The "exercise" portion will then begin. You will be connected to a special EKG machine and then asked to walk on a treadmill. The speed of the treadmill starts slow, and speeds up every 3 minutes. Very athletic people may end up running; however, the average person will stop during a fast walk. At the peak of exercise a second injection of the nuclear agent is given, and a second "stress" set of images is taken.
How to prepare
If you are or may be pregnant, you must tell the technician.

Wear comfortable clothes you would exercise in. Sneakers are preferred; however comfortable walking shoes may also be acceptable. Women may be more comfortable wearing an exercise/sports bra or top.

You may have a light meal before the test; however caffeinated drinks (coffee, tea or caffeinated soda) should be avoided.
Do I take my medications that day?
Yes, unless specifically advised not to do so by your doctor.