go see a cardiologist and have a highly-level heart examination by this specialist. an ecg does not diagnose "innocent murmurs". a murmur is heard by a stethoscope and the determination of it being innocent is one made by the medical professional who is hearing it.
innocent' heart murmur has started to give symptoms. about 8 years ago i went to the gp with breathlessness. following ecg's it was diagnosed as an innocent heart murmur. i went back about 4 years ago with increased symptoms but they said that it was nothing. over the last few years i've been having episodes of palpitations at least a few times a week. until recently i had never fainted before but i've fainted 3 or 4 times alongside these palpitations. is it worth going back to the gp? i feel like i'm going to be told its nothing again.