How a Nuclear Stress Test Works
Stress testing is often ordered with nuclear imaging or echo imaging. During a stress test, sticky pads and wires (electrodes) are attached to your arms, legs and chest to record your heart’s electrical activity. The pads are connected to a computer that measures the electrical impulses that cause your heart to beat. A resting electrocardiogram (ECG) is performed while you are sitting or lying down. A stress ECG is performed while you are walking on a treadmill. The test will tell your cardiologist how your heart is responding to stress and/or exercise.
Patients with coronary artery blockages may have minimal or no symptoms during rest, but symptoms may be present when the patient exercises. During exercise, healthy coronary arteries dilate (open up) more than an artery with a blockage. This unequal dilation causes more blood to be delivered to the portion of the heart muscle supplied by the normal artery. In contrast, narrowed arteries supply less blood to that area of the heart. This reduced flow causes the heart muscle to “starve” during exercise. The “starvation” may produce symptoms (like chest discomfort or shortness of breath), ECG abnormalities and reduced movement of the heart muscle. Your cardiologist can detect this by examining the movement of the walls of the left ventricle (the major pumping chamber of the heart) during a stress test performed in conjunction with echo imaging (echocardiography).
During a nuclear stress test, the blood flow to your heart muscle is measured while you are at rest and when the heart is stressed by exercise or medication administered through an IV (intravenous) line in your arm. A small amount of an inert tracer material is injected into your body. Areas of the heart receiving an adequate blood flow will absorb more of the tracer than those areas of the heart that are not receiving an adequate blood supply. By using special imaging equipment, your doctor can see which areas of the heart are not receiving enough blood flow due to a blockage.
If you have had discussions with your doctor about a stress test, and would like to consider Summa stress testing services, please call us at (888) 926-9540 for more information.