An echocardiogram is a test that uses sound waves to create a moving picture of the heart. A trained sonographer performs the test and it is then interpreted by a cardiologist. An instrument called a transducer that transmits high-frequency sound waves is placed on your ribs near the breast bone and directed toward the heart. Additional images will be taken underneath and slightly to the left of your nipple (at the apex of your heart). The transducer picks up the echoes of the sound waves and transmits them as electrical impulses. The echocardiography machine converts these impulses into moving pictures of the heart. The Doppler probe records the motion of the blood through the heart. An echocardiogram allows doctors to see the heart beating, and to see many of the structures of the heart.