Thanks for writing in to Healthcare Magic!
The superficial vein
on the chest does not indicate or refute any major issue of heart rather the child seems to have got it in legacy.
His fast resting heart rate
can be a problematic issue, you should get him re-evaluated by a cardiologist.
Also get him evaluated for any bronchospasms or asthma
, at times there can be a fast heart secondary to respiratory issues and treating which solves the heart rate issue as well.
If you have any further query please let me know I would try to answer it for you.
Wish you a great health!