Hi PJgirl,
Sorry to hear about the confusion with your daughter. It sounds like they are doing the right studies to address their concerns. It is not uncommon to see a right to left shunt (bubbles going from the right atrium to left atrium) during a bubble study from a small patent foramen ovale (PFO). They often are not apparent on TEE, only through bubble study. Such a small shunt, however, would not cause enlargement of the right atrium and ventricle. IF the second TEE is negative, they could consider doing an MRI to rule out right ventricular dysplasia (RVD), but she really doesn't have the symptoms of RVD from what you are describing.
You didn't mention her pulmonary blood pressure or her right ventricular systolic pressure (RVSP). I am assuming this means she doesn't have pulmonary hypertension.
If she has symptoms of lightheadedness or passing out, I holter monitor or event monitor may help. The record her heart rhythms over time.
Fortunately it sounds like they are doing the right things.
Good luck and thanks for posting.