I have loads of ectopic heartbeats!
Mine are premature ventricular beats, there horrible, but doctors deem them absolutely harmless!
I also have a slow heartbeat, it is as low as 44 BPM sometimes, but i do a lot of running around after my kids, so it more than likely means your fit!
You said you do a lot of exercise, so that is why your heart rate will be slow,so that's a good thing!
Ive had 3 heart monitors fitted and all they see is ectopics, and I get occasional runs of the fast heart rate SVT.
My ectopics are quite frequent at the moment, but you have to keep telling yourself they wont harm you, easier said than done i know!
I think i read somewhere that if your heart rate is slow there's more of a chance of ectopics sneaking in!
Hope you feel better soon!