Cardiac stress test (or Cardiac diagnostic test) is a test used in medicine and cardiology to measure the heart's ability to respond to external stress in a controlled clinical environment. The stress response is induced by exercise or drug stimulation. Cardiac stress tests compare the coronary circulation while the patient is at rest with the same patient's circulation observed 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 on the general physical condition of the test patient. This test can be used to diagnose ischemic heart disease, and for patient prognosis after a heart attack (myocardial infarction). The cardiac stress test is done with heart stimulation, either by exercise on a treadmill, pedalling a stationary exercise bicycle ergometer or with intravenous pharmacological stimulation, with the patient connected to an electrocardiogram (or ECG). People who cannot use their legs may exercise with a bicycle-like crank that they turn with their arms.