ECHO CARDIOGRAPHY, often referred to cardiac echo or simply an echo is a sonogram of the heart. (It is not abbreviated as ECG, which in medicine usually refers to an electrocardiogram.) Echocardiography uses standard two-dimensional, three-dimensional, and Doppler ultrasound to create images of the heart. Echocardiography has become routinely used in the diagnosis, management, and follow-up of patients with any suspected or known heart diseases. It is one of the most widely used diagnostic tests in cardiology.