ACS Q&A – Dr. Fileccia: What Is a Stress Test?

A stress test is used in cardiology to evaluate blood flow through the arteries that supply the heart.

Although the heart pumps blood to the rest of the body, it also needs its own blood supply. The heart receives blood through three main coronary arteries: one on the front of the heart, one on the left side and one on the right side. If these arteries become blocked or narrowed, the heart cannot function properly.

A stress test helps physicians evaluate blood flow to the heart. There are two main types of stress tests: an exercise stress test and a pharmacologic (or chemical) stress test.

During an exercise stress test, the patient walks on a treadmill while connected to an electrocardiogram (EKG). If there is reduced blood flow to the heart, it can cause changes in the heart’s electrical activity that appear on the EKG.

We may also inject a small amount of radioactive tracer into the bloodstream, allowing the medical team to evaluate blood flow to the heart during exercise. If there is a blockage or narrowing in one of the coronary arteries, the scan will show reduced blood flow. This helps us determine how well the arteries are functioning.

A pharmacologic (or chemical) stress test is used for patients who are unable to exercise because of conditions such as knee problems, back problems or other physical limitations. Instead of using exercise, we administer a medication that simulates the effects of exercise. It allows us to evaluate blood flow to the heart and determine whether there is any narrowing of the coronary arteries.