Hello doctors, first of all thank you for your valuable time. I am a 16 year old male. My problem is that when I wake up my hearts beats fast but I don't feel any symptom but the left side of my chest I get the "thud" feeling. It's been like a month I wake up with a fast heart beat and then after breakfast it gradually slows down. Done blood test and ecg both were normal what can be the reason of this and also the cure?