Stress Tests are used by the cardiologist to diagnose cardiac conditions related to lack of blood supply to the heart tissue. During exercise there is increased demand for blood to transport oxygen to the heart muscle. Stress tests are performed while the patient is either physically walking on a tread mill or during pharmacologically induced myocardial stimulation of the heart. Continuous electrocardiogram and blood pressure monitoring is maintained and recorded to diagnose potential conditions that decrease blood flow to the heart muscle. If the stress test indicates a potential lack of blood flow to the heart, further testing, such as a Cardiac Catheterization may be necessary.

During Nuclear Stress Testing a radioisotope is injected into the blood stream and is readily absorbed in the heart muscle. The heart is scanned immediately following the injection and a few hours later to detect the distribution of the radioisotope in the heart muscle. Areas of the heart that do not show an adequate distribution of the radioisotope may indicate that blood flow to that area is compromised and further testing, such as a Cardiac Catheterization, may be necessary.