I am 20 years old and I train football.From unknown reasons my hearth rate increases from 80 to 180.When that happens I blackout and my hands start to shake.I did EKG test, holter, blood test, test load with a limited amount of oxygen. One of the doctors told me that I got fifth muscle and that I need to go to the surgery ,but I don't want to go there without being 100% sure that is the problem. Did somebody faced same symptoms, if you did please contact me. Thank you very much! :]