Morkiemomma, I have this also and I know it can be very frustrating and sometimes scary. After all it is your heart stopping. Who would think that's ok....
Mine does it all day long as in several normal beets and then a skip/stop....a few normal beets ...stop/skip.......It's always on my mind.....I suppose it would be different if I couldn't feel it, but I can, and it causes worry....
I suspect mine may be related to too much caffeine. I drink about 8 cans of diet pop a day and have done this for many years....At least I hope that's s all it is....
I hope you can find the source of yours so at least you can get some peace of mind.....Good luck to you.