S.S.
Two of my friend's kids have it. One diagnosed at 2 and the other at 12. They both had to get monitors to wear around for a day or so. The 2 yr old went on meds everyday the other is just checked periodically. They say it could be stress or hormones. The otehr thing to look at is if there is an imbalance between the left and right brain. The right brain controls respiration so maybe think about bringing the right side up some with physical activites or put her in OT so she can spin and things, it may make the tachycardia go away. Keep the left brain where it is by not teaching letters, numbers etc until much older. There is a great book called Disconnected Kids that talks about this. Turns out the 2 yr old is now 3.6 and has sensory issues so he is starting OT. His right brain is definately low and has been for some time. Maybe after OT he will get off his meds. Let us know what happens.