Just the name "cardiac stress test" sounds ominous, but it's nothing to be worried about. It's a relatively simple test used to assess the performance of your heart when the workload is increased - such as when you are exercising. Sometimes you can have a significant blockage (more than 75%) that isn't evident at rest. It will show up during exercise when the heart is working harder.
Usually the test is done in a doctors' clinic or at a hospital outpatient clinic.
A technician will put adhesive pads on your chest with leads to a monitor - essentially the same as when you have an electrocardiogram (EKG) - and a blood pressure cuff on your arm. Then you will begin walking on the treadmill. Every three minutes the speed and incline will be increased slightly. The doctor will be watching the performance of your heart as shown by changes in the pattern on the EKG as you exercise, as well as tracking your your blood pressure. At intervals you will also be asked if you are feeling any pain and how hard you are finding the exercise. If your heart isn't getting enough oxygen, changes in the EKG will be apparent.
The test will end either when the doctor has enough data or when you give the signal that you can't do any more - whichever comes first.
After you get off the treadmill you will be asked to lie down. As the final part of the test, your doctor will want to see how long it takes your heart to return to a resting state after exertion. This is your recovery heart rate, another indicator of the health of your heart.
The entire procedure will take approximately 45 minutes.
Sometimes a cardiac stress test will be performed using a stationary bicycle.
The cardiac stress test is a very effective diagnostic tool. Occasionally, particularly in women, the results are not accurate - a slight blockage may be missed (a false-negative), or more often the test will suggest heart disease when it doesn't exist (a false-positive).
Also known as a myocardial perfusion imaging test, this test shows how blood flows to the heart. If it's required it's generally done along with a regular stress test.
When you reach your maximum level of exercise, a small amount of a radioactive substance called thallium is injected into your bloodstream. You then lie down on a special table under a gamma camera that can "see" the thallium. As the thallium moves through your bloodstream and enters your heart, the images will show if part of the heart muscle isn't receiving a normal blood supply.
The first images will be taken immediately after the exercise test. Over then next couple of hours more images will be taken. This is to show the comparison of blood flow to the heart muscle during stress and at rest. This heart test can reveal areas where blood flow is reduced as well as scar tissue from a previous heart attack.
If you are too ill to do a cardiac stress test or if you have mobility problems, a drug can be given to increase blood flow to the heart to mimic the effects of the exercise test.