I came across these posts while researching heart palpitations.  I've been getting them for about 3 months - so scary.  Just as soon as I thought they'd gone away they'd come back.  I also wore a Holter Monitor and had an echocardiogram, also negative.  Dr. said to go for walks and try to relax.  I would do that but they would come back anyway.  When I read your post it rang a bell because it had gone through my mind that it might be calcium deficiency but then just forgot about it. I had been taking my calcium supplements only sporadically since menopause.  Because of your post I bought a Caltrate calcium supplement that contains magnesium.  I make sure that I don't skip taking them at all.  Do you take a separate magnesium pill and what kind of magnesium is it?  Plus I've been eating foods rich in magnesium. Anyway it's been about a week since I've had heart palps but better than that I have a lot less body aches and just feel so much better.  I didn't realize how incredibly lousy I'd been feeling until I started feeling better. I'm crossing my fingers that the heart palps don't come back but thank you, thank you, thank you!