Hi guys and thanks for taking your time reading this. Im sorry if i make some grammas mistakes because my english is not the best .. Well let me begin first im 16 years old and im 180cm and weigh around 60 kg. I really like sport. I have been on basketball since i where around 8 and i still play it. Around a year ago i where in a match and i where going at it. Sprinting, pushing my body to the limit, because we where doing not that well and we needed the win. So all of a sudden when i did my full 100% sprint, i felt my heart go like 3x faster then when i normally sprint so it really scared me and i immediately stopped playing and told the referee that he had to stop the game. My coach told me to sit down on the ground. so i sat down and i tried to feel how it did. I felt like i had 2 hearts beating at the same time very rapidly, and i sat there for like 2 minutes while everyone was looking at me, and all of a sudden my heart just instantly went to normal speed. it felt like something was stuck in my heart and my heart finally managed to pop it out after like 2 minutes. So my mom was really worried like myself. So we went to a cardiologist he look at my heart with the thing thats used to see how the baby is when someone is pregnant. and after that i had to cycle for a while, while they kept putting more pressure and the pedals and i had to try keep the same speed while they measured my heartbeat. But i had no strange heartbeat i had that match. So then they but a box on me that measured my heart for 24 hours and i didnt have that strange heartbeat as at the match either. So the result was that i had no heart problem. I where really curious why my heart would do that... But i didnt wanted to worry and the cardiologist told me there was nothing wrong so i believed him. But like after 6 months when i where having a training lesson with my team. I sprinted again and all of a sudden instantly again that fast double heartbeat came, this time it didnt scare me but i thought it would be better to stop, so i stopped, and again my heartbeat went from double fast heartbeat to normal heartbeat after i sat down for 2 mins it just instantly in like half a second went to normal. so i where like hmmm it should be that bad if the cardiologist told me its not bad. So around 3 months later u where again having a trainings lesson from basketball. And again when i sprinted i suddenly got that double fast heartbeat. I where like well it shouldnt be that bad i think. so i kept playing for like 2 minutes while my heart was going very fast and it didnt go away, and i still put alot of effort on my body. then i felt like a where gonna faint, my head felt very lightweighted and my eyesight became very weird, when i looked at a friend i saw darkness around the edges of my vision and it kept becoming bigger and bigger until i saw i little circle while the rest was black (this happend in like 5 seconds) So i thought i could maybe pass out if i wouldnt stop so i instantly stood still and in like 30 seconds my heartbeat instantly popped to normal again and my eyesight became normal in like 10 seconds.
Thx for reading this far and please can anyone tell me whats going on because im pretty scared at the moment...