Recently, About 2 weeks ago, i was at my Grandparents house When i Jumped off the diving board into the water. This was not the first time that i had jumped off, but as i got out of the water and was walking back onto the diving board, My heart began to beat Very hard. I asked my friend Patrick to feel me heart to make sure it was actually beating hard and fast (wanted to make sure it wasn't just in my head). When he felt it, He said it didn't seem right. I'm not sure if its linked, but about 5 years ago, when i was in the 4th grade, I was in the hospital where they Discovered i had a Heart murmurer and a leaking valve, which the doctors sad was probably there from birth. Earlier today, It happened again where my heart began to beat hard and fast. i was sitting down on my computer playing WoW, and it happened. i then felt light headed. both times, it lasted for about 20 seconds-30 seonds. Does anyone know whats wrong?