My son was born with ASD (atrial septum defect) he had a moderate sized hole in his heart that has since closed on its own. Because of this, they have me scheduled for an echocardiogram tomorrow for his baby brother, just to see if he has the same defect. What can I expect? They said it would be at least a 1.5-2 hour procedure. How does one do an echo on a fetus anyway? I'm not nervous or anything. Just curious as to what it entails.