Any of various tests that assess cardiovascular health and function after application of a stress to the heart, usually exercise but sometimes others such as atrial pacing (regulation of the heartbeat by means of an electrode inserted in the atrium of the heart) or specific drugs. In an exercise cardiac stress test (ECST), the patient exercises on a treadmill according to a standardized protocol, with progressive increases in the speed and elevation of the treadmill (typically changing at three-minute intervals). During the ECST, the patient’s electrocardiogram (EKG), heart rate, heart rhythm, and blood pressure are continuously monitored. If a coronary arterial blockage results in decreased blood flow to a part of the heart during exercise, certain changes may be observed in the EKG, as well as in the response of the heart rate and blood pressure.