MAGNESIUM!!
I've been having ectopic heartbeats for almost a whole year now. Heart beats three times, then skips one, then BOOM a big one, then a couple little ones, then it skips one, then BOOM. Sometimes it will happen all day long, sometimes only when I'm exhausted and trying to fall asleep.
Nothing I found ever helped except getting up and moving around, but that only helps for a few minutes, I even went to the ER from panic attacks associated with the alarming rhythms but it would always magically stop once they hooked me up to the heart monitors. I have low potassium so I took supplements but didn't really make a huge difference.
Just yesterday I learned about over the counter magnesium supplements as an aid for ectopic heartbeats, there was a case study with about 1,000 people and the result was with a larger dose (at least 300mg) over 80% of them reported "good" or "very good" results in getting your heart beating in a regular pattern. So this morning I went and bought some, took 500mg with food and water, and my ectopic heartbeat went away in about 20 minutes. It has been beating normally all day for the first time in months and the relief is incredible.
It's such an uncomfortable issue but magnesium has finally done the trick for me, I hope you try it and let me know if it helped you too.