Just a quick note to say that cardiology cleared her of having any heart related reason for her symptoms. We did get an echocardiogram, so they feel pretty definitive that she is no more likely to drop dead than any other 6 year old. So that is GOOD NEWS. She does have a slight defect, but not one that would effect her health and it is not necessarily more or less than anyone else might have. She does still have her double heart murmurs which they are confident are both innocent and said that her very thin chest can amplify (to us and residents at ER and such who are often alarmed) her heart beat and draw attention to her murmurs when they might otherwise go unnoticed. So when her heart feels like it is beating out of her chest it is mostly because it is just so close to the surface.
They are also mystified and concerned about her weird exhaustion. They suggest we get a Peak Flow monitor and see what is going on with her breathing... some kids have asthma without prominent wheezing. They also suggest we get her tested for mono.
So, still some stuff to go before we have an answer, but right now we have ruled out the deadly possibilities so I'm good with that.