Hi. i sometimes feel weird a weird hear beat when im

Hello, my name is mike i am 17 years old 6 foot 6 205 pounds. i am very athletic i run everyday for a hour and go lift weights so i don't think im out of shape.well i should let you guys know that in december i had a anxiety attack i felt my heart beating reaaaallly fast. i went to tthe heart doctor he did a electrocardiogram,stress test,thyroid test, blood test,ekg, and a 24 hour holter monitor  all turned out to be normal. He did put me on metroprolol but he told me something about to much adrenaline going to my heart or something but he told me i was perfectly healthy and this was nothing to worry about ive been on metroprolol for 5 moths im going back to the doctor thursday too see if he should higher the dosage but i haven't experienced any fast heart beats. we have this machine at home that measured my heart rate and my heart rate resting at night is usually anywhere from 54 to 65 beats per minute im guessing that is because im athletic my blood pressure is usally any where from 110 to 130. well anyway saying all that ive been getting this weird heart beat like i would feel the heart beat kind of hard to explain the feeling idk but it feels like a messed up beat . im just worried it might be like a dangerous thing idk i dont ever get them when i run or anything just when im resting. i dont feel light headed or anything the beat just feels weird usually just one beat and the rest are normal what could this be?

[heart sick]

Sounds like run of the mill heart palpitations. Its like skipping a beat very scary but Dr's always say nothing to worry about. To be sure I waould ask cardio Dr. for an event monitor for 30 days that way you can push the button every time your heart flutters and they will be able to yell you if they are benign or not. Good luck :)