An echocardiogram is a noninvasive test that uses sound to produce images of the heart. In the standard echo test for the heart the technician applies gel to the chest and presses a device that detects sound waves from the heart to create computer generated image, according to Mayo Clinic.
The echo test provides information on heart size, strength, valve size, heart disease and damaged heart muscle, reports Mayo Clinic. This information allows the doctor to evaluate the strength of the heart and its ability to supply blood to the body.
In some patients, the standard echocardiogram does not show the information the doctor needs. In a transesophageal echocardiogram the technician directs an instrument into the patient's esophagus. This echo test provides detailed pictures of the heart. It requires numbing of the throat during the testing time, indicates Mayo Clinic.
When a doctor is interested in heart problems that occur during physical activity, Mayo Clinic indicates that he orders a stress test. During the stress test, the echocardiogram records the heart activity while the patient walks on a treadmill. For patients who have difficulty with exercise, the doctor injects a chemical into the bloodstream that increases the heart without exercise. These tests are especially useful in diagnosing coronary artery disease.