What is a Stress Test, and What Does it Tell us About the Heart?
At rest, your heart may appear to be working fine. However, when you “stress” your heart and cardiovascular system by exercising, your heart rate and blood flow increase in order to provide your cells with more oxygen and nutrients and remove waste.
The stress test allows your doctor to see how your heart functions under stress. This way, any signs and symptoms of heart problems will be more pronounced. The most common type of stress test is an exercise stress test on a treadmill that gradually increases in speed and grade. However, if you are not able to exercise by walking on a treadmill, you will be given a drug that simulates the effects of exercise by making your heart beat faster.
During the stress test, your electrocardiogram (EKG), heart rate, and blood pressure are monitored. The EKG measures the electrical activity that moves through your heart with each heartbeat, and a healthy heart produces a specific pattern of response with each heartbeat. If your heart is not working properly, this pattern is altered. Along with your heart rate and blood pressure, the information obtained from the EKG enables your doctor to detect any heart problems. Heart problems commonly found through a stress test include abnormal heart rhythms, inadequate blood flow, heart valve malfunction, and the presence of coronary artery disease.
If there is a problem with your heart, your doctor may also want to visualize your heart during the stress test. Imaging techniques often used in combination with the stress test are the echocardiogram and nuclear imaging. The echocardiogram enables your cardiologist to see the size and shape of your heart, thickness, and movement of your heart muscle; how well the chambers and valves in your heart are working; and the force with which your heart contracts. Nuclear imaging shows your cardiologist how well your heart pumps with each heartbeat.
The type of stress test requested by your doctor will depend on your specific medical condition and test results. Your cardiologist will want to know this information in order to give you the best possible treatment.