Echocardiography is noninvasive with no known harm to patients. However, it incurs significant cost and therefore should be used judicially. Pediatric echocardiography should be performed by pediatric cardiac sonographers and interpreted by pediatric cardiologists trained in this field to avoid overlooking congenital heart diseases. Imaging and interpretation by specialists outside the field of pediatric cardiology is likely to lead to errors. Echocardiography shows cardiac anatomy through 2D imaging. Blood flow, both normal and abnormal can be studied through color Doppler. Pressure gradient measurements is determined by Doppler flow velocity measurement. Echocardiography is poorly equipped to see peripheral pulmonary arteries and veins.