There are many reasons why your doctor would want to order a stress test. The most common reason is probably to assess symptomatic chest pain, with the overall goal to diagnose obstructive coronary artery disease. Coronary arteries are the vessels that supply blood to your heart. While at rest, most people receive an adequate amount blood to the heart, and do not have chest pain. When we have to exert ourselves with moderate to intense activity, our heart muscle receives more blood to support an increased demand to perform a higher workload. Ischemia is a condition whereas there is an inadequate supply of blood to meet the demand of the heart, which can cause chest pain. We can diagnose patients with obstructive heart disease by inducing a stress state in the lab and monitor for ischemia.
There are several ways to induce a stress state. The most straight forward approach is with jogging on a treadmill. We can also induce a stress state pharmacologically using dobutamine, adenosine and lexiscan.
Ischemia can be evaluated by EKG alone; or an imaging technique such as echocardiogram or a nuclear scan can be performed to help localize the distribution of the ischemic myocardium. The algorithm used to decide how to achieve the stress state and how to assess for ischemia depend on multiple characteristics of the individual patient.