Jerry, you have to be careful with the meds. I dont know if it affects the afib or not but I read tylonal pm CAN, cause a fast, pounding, or uneven heartbeat.
Having rythm issues, I always research the side effects on the heart. Remember there is the short list of side effects, and the long list.
While not specifically for PVC, I have used melatonin and some concoctions like "Nightsrest" and none have improved my sleep. I don't think they made it worse either, seems to be about the same. I have also use PM pain killers, Tylenol/Similar. No benefit here either. I may have tried both at the same time.
I do not think my heart symptoms (AFib) keep me awake, but I do have trouble with dreams.
ps, my natural doc said melatonin is not as safe as everyone says. I found this info-its not a medical site though
http://www.ehow.com/facts_5017675_longterm-effects-taking-melatonin.html
Lots of people have good results with tart cherry juice but it takes a month or two to work. I am against herbs, drugs, etc..., but have tried this, not much luck for me, but I was not faithful in using it either (tasted tart, like cranberries).