What Does Stress Testing Show?

Stress testing provides your doctor with information about how your heart works during physical stress (exercise) and how healthy your heart is. Standard exercise stress testing uses an EKG (electrocardiogram) to monitor changes in the electrical activity of your heart. Imaging stress tests take pictures of the blood flow to different parts of your heart.

Both types of stress testing are used to look for signs that your heart isn't getting enough blood flow during exercise. Abnormal results on stress testing may be due to coronary artery disease (CAD), but also can be due to other factors such as a lack of physical fitness.

If you have a standard exercise stress test and the results are normal, no further testing or treatment may be needed. But if your standard exercise stress test results are abnormal, or if you're physically unable to exercise, your doctor may want you to have an imaging stress test or undergo other testing. Even if your standard exercise stress test results are normal, your doctor may want you to have an imaging stress test if you continue having symptoms (such as shortness of breath or chest pain).

Standard exercise stress testing isn't equally accurate in men and women. Normal results from a standard exercise stress test usually accurately rule out CAD in both men and women. But a standard exercise stress test can show abnormal results even when the patient doesn't have CAD (these results are called false positives). False positive exercise stress tests happen more often in women than in men.

Imaging stress tests are more accurate than standard exercise stress tests (in men and women) because they directly show how well blood is flowing in heart muscle and reveal parts of the heart that aren't contracting strongly. But imaging stress tests are much more expensive than standard exercise stress tests.

Imaging stress tests can show the parts of the heart not getting enough blood, as well as dead tissue in the heart, where no blood flows. (A heart attack can cause some tissue in the heart to die.) If your imaging stress test suggests significant CAD, your doctor may want you to have more testing and/or treatment.