Maybe a pediatric cardiologist would put your mind at ease or at least give you an indication of what is normal. Unfortunately a lot of adult cardiologists have no experience with children. I'd make an appointment with one. BP sounds okay to me, but I'm no doctor! Mine is 90/40 when I'm at rest in bed, but I take BP meds
A normal Hr in a Healthy 10 year old male should be about (resting like in a chair) about 70-110 sleeping should be about 60-100 and playing can go up to 180. That doesn't mean to say something is wrong if you have a little difference. as for his BP about 102/62
I have a 4 year old son who has a significant cardiac history his HR goes can go over 200 while just sitting and there has been times where his Hr has gone as low as 47 and he has passed out. now a 4 yr old and 10 year for HR fall in the same beats. Chris has had a cardiac cath and a electrophysiology study done by a pediatric doctor. they say it can be normal to have a low HR like in the 40's (without symptoms like passing out, that is not okay) and it can go as high as 200 and be normal. due to the fact he could be watching TV and something scares him and makes him jump.
In my opinion, I would seek a pediatric cardiologist. I am not convinced that a HR while sitting there can go that high. they have his holter monitor showing his highest level at 178 and they said he was very tachy but he is okay. I am sure that the cardiologist will run an echo on him.
I hope nothing is wrong with your nephew. good luck, oh by the way Chris was suppose to get a pacemaker in june, but now it is a wait and see. I am not convinced that there isn't something wrong.
good luck
Michelle