An echocardiogram (also called echo, transthoracic echocardiogram or TTE, exercise or stress echocardiogram, dobutamine stress echocardiogram or DSE or transesoophageal echocardiogram or TEE) is a noninvasive (the skin is not pierced) procedure used to assess the heart’s functions or structures. A transducer sends out ultrasonic sound waves at a frequency too high to be heard. When the transducer is placed on the chest at certain locations and angles, the ultrasonic sound waves move through the skin and other body tissues to the heart tissues, where the waves echo off of the heart structures. The transducer picks up the reflected waves and sends them to a computer. The computer interprets the echoes into images of the heart walls and valves.