An echocardiogram is a noninvasive (the skin is not pierced) procedure used to assess the heart's function and structures. During the procedure, a transducer (like a microphone) 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 and blood vessel tissues, where the waves bounce or "echo" off of the structures. These sound waves are sent to a computer that can create moving images of the heart walls, blood vessels and valves.