Can Migraines And The Rapid Heart Rate Cause Dizziness?

My daughter is 16 years old weighhs about 120 and is 5 4 tall. She has recently been having headaches and dizziness. She fainted a few times during this. Her heart rate is about 120 to 142. Doctors have ran all kind of test.They have did 2 CAT scan, MRI of the brain, 3 EKG s, eyeball ultrasound, plenty of blood work, and urine test. All came back okay except One neuro said that there was a small tiny spot on the MRI image that he considers it migraines. She has been in the hospital for 4 days. They have been treating her for migraines. The EKG was fine except that her heart was racing. The doctor is releasing her today with 2 prescriptions, one is depakote for migraines and one to reduce her heart rate. She is still complaining that her head hurts and she is still dizzy. I guess my question is Can the migraines and the rapid heart rate make her dizzy all the time?