hi, my name is Zaki. My daughter had the same problem when she was nine, but only she would knock at my door at 1 a.m. crying of irregularly fast heartbeat, chest pains , nausea , and worst stomach spasms. The EP wanted to wait till she's 12, the Paeds Proffessor didn't know what to do. So i bought a handheld ECG event recorder and books on cardiology and EKG, got the printouts when she has the event and presented to a good friend of mine but who happens to be a cardiologist. He gambled by starting her on Propanolol and she was fine. Now 4 years later, she 's almost off the medication and only takes it when required. And since i also had the same problems, i guess it' s genetics. Good luck...
Unfortunately there is no way I can answer your question given the information provided. It really depends upon how fast your child's heart rate was documented to be, whether the baseline ECG is normal or not, what the ECG looked like when the heart rate was fast, what kind of symptoms she had, whether her heart is structurally normal or not. Depending upon whether or not there is a true arrhythmia (abnormal type of heart beat, not just the usual heart rate speeded up), there are medications and other therapies that can be used. If it is just her usual heart rate speeded up, than can sometimes be secondary to other medications. Heredity does have to be considered, but it really depends upon what type of heart rhythm problem your mother had, and if that is the same of different from your daughters case. If you are dissatisfied with the information that you have gotten from your current providers, then I would recommend seeking a second opinion from a pediatric cardiologist with expertise in heart arrhythmias (an electophysiologist or EP doctor, for short).