Cardiac stress testing (or cardiac diagnostic testing) is a test used to measure the heart's ability to respond to external stress in a controlled clinical environment. In many instances, the presence of coronary artery disease (CAD) is easily missed when you are at rest, because when at rest, there may be no sign of a problem. In these cases, cardiac abnormalities may become apparent only when the heart must perform at increased workloads.
The stress response is induced by exercise or drug stimulation. Cardiac stress tests compare your coronary circulation while at rest and during maximum physical exertion, showing any abnormal blood flow to the heart's muscle tissue (the myocardium). The results can be interpreted as a reflection of your general physical condition. This test can be used to diagnose ischemic heart disease (reduced blood supply to the heart muscle), and for your prognosis after a heart attack (myocardial infarction).