Pharmacologic Stress Test - Diagnosing Heart Disease: Heart Disease

Content provided by the Faculty of the Harvard Medical School

Pharmacologic stress test

Some people with arthritis, vascular disease, or other medical conditions just cannot exercise enough to undergo the traditional exercise tolerance test. In such situations, a pharmacologic stress test, which substitutes medication for exercise, provides another option. The medications used increase the heart's need for blood, allowing doctors to detect blockages that obstruct the supply of blood.

Two strategies are commonly used in pharmacologic stress tests. In one, the medications used — dobutamine, which acts like adrenaline and is sometimes combined with atropine — increase the amount of work the heart does, thereby increasing its need for oxygen-rich blood, much as exercise does. Echocardiography (see below) is generally used to monitor abnormalities induced by dobutamine. A second strategy is to give dipyridamole (Persantine) or adenosine (Adenocard), medications that cause the coronary arteries to widen, producing a fourfold increase in blood flow. Blood flow does not increase in blocked arteries, which can't widen. Nuclear imaging (see next section) is usually used to detect blockages revealed by dipyridamole or adenosine.

Pharmacologic stress tests aren't for everyone. People with asthma, emphysema, carotid artery disease, or aortic stenosis should not take dipyridamole or adenosine, while anyone with uncontrolled hypertension or abnormal heart rhythms should not take dobutamine. But for many people, pharmacologic stress testing is safe.

Last updated:	May 03, 2007