An echocardiogram (also called an echo) is a type of ultrasound test that uses high-pitched sound waves that are sent through a device called a transducer. The device picks up echoes of the sound waves as they bounce off the different parts of your heart. These echoes are turned into moving pictures of your heart that can be seen on a video screen. Echo can be used as part of a stress test and with an electrocardiogram (EKG) to help your doctor learn more about your heart. It is also used during open heart surgery.