While you walk, electrodes (sticky patches) that are attached to your chest and limbs send signals to an electrocardiogram (ECG/EKG) machine, which creates a readout of the heart’s electrical activity. The continuous recording from the electrocardiogram taken during the stress test evaluates if there are any changes consistent with a portion of the heart not receiving enough blood flow. Whether you feel chest pain or other symptoms when your heart is “under stress” may indicate to your doctor the presence of any blockages in the arteries that supply blood to your heart.
In addition to the continuous recording of the electrocardiogram, your doctor may obtain images during the stress test through an echocardiogram (ultrasound) to assess the flow of blood. You may also receive a nuclear stress test, for which a small amount of radioactive tracer will be injected into your bloodstream. These imaging tests may be needed for some patients to increase the accuracy of the stress test.