Your doctor may ask for a stress test to find out how well your heart is working. A scan, called a stress echocardiogram, records what happens to your blood flow as your heart pumps faster and harder and transmits this information into computerized images. Results can reveal possible problems within the arteries, such as narrowing or blockages from plaque or scar tissue, or structural issues such as a faulty heart valve.

First, an ultrasound technician will take a scan of your chest using a wand-shaped device (transducer) while you’re at rest and lying on your left side.

Next, you’ll have electrodes placed on your chest, arms and legs that monitor your blood pressure and heart rhythm. Then you’ll walk or slowly jog on a treadmill or pedal an exercise bike for 5 to 15 minutes. If you’re unable to walk or pedal, you’ll receive an injected medication, dobutamine, to increase your heart rate. This is called a dobutamine stress echocardiogram.

If you’re on a treadmill or bike, your doctor will instruct you to stop once you’ve reached a target heart rate, you become too tired to continue or you experience any pain or abnormal blood pressure readings.

Nuclear Stress Testing

Your doctor may alternately suggest a nuclear stress test, which uses an injected radioactive dye to view your heart arteries’ blood flow. You’ll receive the dye during the resting portion of the test, and again after you’ve exercised. If you are unable to exercise, an IV will be placed and a medication will be given to help detect regions of reduced blood flow.

After each injection, you’ll undergo a noninvasive scan — either a cardiac SPECT (single photon emission computed tomography) or cardiac PET (positron emission tomography) — in a doughnut-shaped scanner, which transmits images of the dye moving through your arteries to a computer. This way your doctor can see healthy and damaged heart structures to help determine the best treatment course.