Echocardiography involves a non-invasive diagnostic test that uses ultrasound waves to create either two-dimensional or three-dimensional images of the heart chambers, valves and surrounding structures. The images are called an echocardiogram. Electrocardiography is a way to diagnose, evaluate and monitor such things as: heart pumping function and output; murmurs; abnormal heart valves; damage to the heart muscle following a heart attack; infection or inflammation in the sac around the heart (pericarditis); infection on or around the heart valves (infectious endocarditis); the source of a blood clot after a stroke; and congenital heart disease (malformation of the heart or the large blood vessels near the heart).