Hi My Daughter Has Near Faint Episodes It Has Started

Hi my daughter has near faint episodes it has started in the last week she has had two episodes in the last three days she has had an MRI of the brain and spine and everything is clear she has also had an ultrasound of her heart and that was good as well. The doctors we have seen have told us to take multivitamins and keep her electrolytes up but even doing this she had an episode yesterday . I don't want this to affect her life she's a busy girl with uni and a partime Jon. She also goes to the gym at least three days a week. I'm so worried about her having an episode when no one she knows is around . We are seeing a cardiologist at the end of January are there any treatments or further strategies we can use.