I hope this isn't a showstopper for you. Lots of people have irregular heart rhythms.
However, never go for an FAA medical or put a mark on that FAA 8500-8 form unless you know in advance that you don't have a disqualifying condition. If you suspect you have something wrong, talk to your GP first--off the record if he'll accommodate that.
Also, ask around before you select your next FAA medical examiner. Try to find one that's a pilot. Go across the state if you have to. There are all kinds. I've had guys who were as picky and others who barely looked at me. Most of us know when we are safe to fly and the others don't care and fly anyway.