is an ultrasound
of the heart. It gets a visual of all of the heart's chambers, valves, size of the heart and how well is contracts. It sounds like the doctor heard what is called a "murmur" and wants your daughter to have this test so it can be determined what could be causing the abnormal sound. It is not painful to have one done. I'm not going to say "don't worry", as it is appropriate to be concerned. Look at it this way: If she was in imminent danger, she would be in the hospital as we speak. I imagine you are scared. I hope things go well for you and your daughter. It sounds like your daughter is in good hands. I hope things turn out okay.