I had some severe heart palpitations recently and my heart hasnt felt 'the same' ever since?

It was a hot day at school and i was running around having a kick with my friends. All of a sudden i feel my heart racing and beating with unbelievably heavy pounding. I sat down but it got harder, and evry minute felt like an hour, i eventually lied down, though once i closed my eyes i felt dizzy. I was taken to hospital by ambulance.

This lasted about 7 minutes, after it slowed down (was still beating fairly fast, but nuthing compared to wen it first happend) our first aid teacher said to me 'thats the fastest and hardest heart beat i've ever felt. It honestly scared me.'
Im 17, just b4 the incident by 8 days my uncle passed away from a cardiac arrest. Strong family history.

I had an echocardiogram, they said the structures fine, but im still waiting for more tests to be carried out.

Any information will be gratefully appreciated.

Since you are so very young you need to have a complete cardiac workup. You had an echo cardiogram which ruled out any structural problems with your heart. You need to wear a holter monitor which would give your Dr a continuous ecg tracing for 24 hours. When you wear it you must engage in all your normal activities to try to capture what happened to you at school. I'm assuming your Dr ordering bloodwork and checked your thyroid functioning.What did the hospital say (and do) when you went to the emergency? Once you have had all necessary tests done you must get a referral to a cardiologist and if an arrhythmia is documented your should be referred to a cardiac electrophysiologist who might investigate your heart rhythm problems more invasively.Until that happens I don't think you should be running until you get the all clear. Take care, Donna