What Does it Mean When Someone is Experiencing Irregular Heart palpitations?

Question :

My brother, 18, veeerrrryyy healthy, he works out every day, eats right, protein shakes and such and drinks plenty of water, milk, juice, rarely soda. hes been experiencing irregular heart palpitations and "fluttering" and his heart beats as if he waas just running but hes not, hes sitting down relaxing. our aunt has heart disease, but this is the first signs hes had. what could this be? thank you very much!

Answers :
Teenagers who are very healthy are more prone to these feelings it's probably because his heart is beating lower than 60 as it's so strong and healthy but as it beats that slowncan cause sensations, inpersonallunwould go to ER for an ECG so A professional doctor can Give there opinion .