Does Dehydration Cause Recurring Episodes Of Syncope In A Teenager?

My daughter is 14 years old and has recently been conditioning for high school basketball. She has had 2 episodes of syncope. The first episode occurred 2 years ago, to the day, and the most recent was a week ago. Both times she was found on the floor and woke up very confused. The first incident occurred when she was getting ready to shower and the most recent occurred while getting dressed. Both incidents were within an hour of waking up. Both times she has been rushed to the ER. At the ER, they performed a EKG, ct scan of the brain, chest X-ray, glucose test, blood work. After the first incident, they did a sleep deprived EEG. All tests were normal. They said she fainted due to mild dehydration and growth spurts. My daughters pediatrician has referred us to a cardiologist as a precaution. The appointment is tomorrow. I m very worried, Does this sound like a correct diagnosis?