March 21st, 2013
Chemical Stress Testing
A chemical stress test is used when a traditional stress test (called a cardiac stress test) cannot be done. A cardiac stress test requires you to walk on a treadmill or ride a stationary bicycle until your heart rate reaches a level where your heart is “stressed”. You may not be able to participate in this kind of test if you have a condition such as a stroke. In this case, a chemical stress test is used. This test is used to help your doctor determine if you have any kind of heart condition causing the chest pain, if arteries to the heart have blockage or narrowing, identify an irregular heart rhythm, monitor the heart’s response to treatment or procedures, and plan rehabilitation after a heart attack. A stress test is a clinical standard often used to detect coronary artery disease. The imaging portion of the test is identical to that used during stress echocardiography or isotope stress testing and is performed either in a cardiologist office, a satellite lab or the hospital. An intravenous line is started in the arm, the blood pressure is checked and an EKG recorded. Common medications used for a chemical stress test include dipyridamole, dobutamine, and adenosine. Medication is supplied until 85 percent of your age-predicted maximum heart rate has been reached. In the initial phases of exercise in the upright position, cardiac output is increased by an augmentation in stroke volume meditated through the use of the Frank-Starling Mechanism and heart rate. Treadmill stress testing is the test of choice when a patient is able to exercise because of the physiologic effect that exercise has on the blood pressure and heart rate. It also helps give the physician an idea about the patient’s exercise tolerance and whether or not the exertion has any adverse effects on the patient’s symptoms or irregular heartbeats. The treadmill test involves walking on the treadmill at a...