It is also normal in most people to feel a racing heart. if you have a primary doctor set up an appt. withtem. it can only help make everyone involed feel better knowing what is going on. if it is anxiety, maybe he can then get control of it or find out what is going on.
good luck and he shouldn't have to worry a his age about his heart and dying, so I would have it checked just to ease his mind if anything
michelle
......and as far as the EKG goes, yes they would have picked up any cardiovascular abnormalities as well as the chest X- ray with those tests.
Your nephew is most likely suffering from panic/ anxiety related episodes. The symptoms can range from breathlessness to rapid heart beat. In fact, in some cases, it seems as though you are suffering a heart attack! Panic attacks typically go away after 15-20 or sooner with medication such as benzodiazeines or just breathing relaxation exercises like pkdonlon alluded. The tingling sensation your nephew is experiencing is also from hyperventilating from a panic attack. It is extremely unlikely there is anything cardiovascularly wrong with your nephew given his age, however if this problem persists you could always sit down with your primary care doctor and he/she could refer you to a cardiologists if there is the need!
Have you considered that maybe he is experiencing some anxiety? My brother complained of the same symptoms as well as muscle aches and some others at that age and it was diagnosed as anxiety as much as he thought it was his heart. My husband experienced the same sort of anxiety at that age and was taught relaxation techniques by his doctor.