Hi! Good morning. I am Dr Shareef answering your query. Once all the tests have come out to be normal, the only chance of getting it diagnosed is to report to an emergency room or to the cardiologist at the time your daughter gets the symptom of rapid heart rate. Usually it is investigated by people who have got experience in electro-physiological activity of the heart in the cardiology unit.Management would depend on this. I hope this information would help you in discussing with your family physician/treating doctor in further management of your daughter s problem. Please do not hesitate to ask in case of any further doubts. Thanks for choosing health care magic to clear doubts on your health problems. Wishing you an early recovery. Dr Shareef.