In the context of electrocardiography (ECG), "stress" refers to the physiological demands placed on the heart during physical exertion or pharmacological stimulation. An ECG stress test assesses how well your heart functions under these conditions.
Understanding ECG Stress Tests
An ECG, or electrocardiogram, records the electrical activity of your heart. During a stress test, your heart rate and rhythm are monitored via ECG while you exercise (typically on a treadmill or stationary bike) or are given medication (like dobutamine) to increase your heart rate. This allows doctors to evaluate the heart's response to increased workload.
Types of ECG Stress Tests
Several types of stress tests exist, including:
- Exercise ECG (Exercise Stress Test): The most common type; involves physical exertion to stress the heart. As noted in the Cleveland Clinic article (https://my.clevelandclinic.org/health/diagnostics/16984-exercise-stress-test), this typically involves treadmill walking or stationary biking.
- Pharmacological Stress Test (e.g., Dobutamine Stress Echocardiogram): Used if a patient cannot exercise adequately; medication increases heart rate and contractility, simulating the effects of exercise. The Johns Hopkins Medicine website (https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/dobutamine-stress-echocardiogram) details the use of dobutamine.
- Stress Echocardiogram: Combines an ECG with an echocardiogram (ultrasound of the heart) to assess both electrical activity and heart muscle function during stress. As described in the Cleveland Clinic article (https://my.clevelandclinic.org/health/diagnostics/16983-exercise-stress-echocardiogram), this produces moving images of the heart.
What the Test Shows
The ECG portion of a stress test identifies any abnormalities in heart rhythm or electrical conduction that may only appear under stress. Changes in the ECG during exercise can indicate underlying heart conditions like coronary artery disease. The Mayo Clinic (https://www.mayoclinic.org/tests-procedures/stress-test/about/pac-20385234) explains that blood pressure is also monitored during the test. The British Heart Foundation (https://www.bhf.org.uk/informationsupport/tests/exercise-ecg) also refers to this test as an "exercise tolerance test."
