Thank you for submitting your question. A normal EKG ruled out arrhythmia as a cause of her fainting episodes. However, there are other causes of syncope(passing out) that are serious and should be considered.
For example, if she passed out while playing sports/exercising, then she must have an echocardiogram to rule out structural heart disease. A disorder called hypertrophic cardiomyopathy can cause symptoms of syncope. It is a rare disorder, but can lead to premature death if untreated.
If her syncope episodes are related to posture(e.g. standing up from a sitting position), then anemia should be ruled out. This type of syncope is called orthostatic hypotension. It is a sign of anemia or low blood pressure.
Seizures can cause loss of consciousness, but generally last longer than seconds, and are associated with arm/leg movements.
I hope this is helpful to you. Again, if she passed out while playing sports, get a referral to see a pediatric cardiologist right the way.