I take viamin K2. I first started taking it five years ago when I read that it is supposed to help put calcium in the bones and not in the coronary arteriea so it's supposed to help prevent or reverse coronary calcification - I read all about it and read a study done in Holland regarding it. I did not, and do not, have coronary calcification but I had calcification on my bicuspid aortic valve so I decided to take the K2 on the off chance it might help slow down the calcification. No studies have been done on that I might add. Wherther or not it helped me who knows as there's not a copy of me in a parallel universe who did not take K2 LOL When I had AVR the valve was "moderately calcified" , though I had severe stenosis. The other reason I take K2 is that I have osteoporosis. In Japan vitamin K2 is a prescribed treatment for osteoporosis, and currently in the UK one of the large London hospitals is starting a trial using it in the treatment of osteoporosis.
I take 300 mcg of K2 per day. I take a supplement called 'Super K' (made by Life Extension) which contains 200 mcg of vitamin K2 as MK-7. I take two on alternate days, on on the other alternate day, so that it averages 300 mcg per day.
The book: "Vitamin K2 and the Calcium Paradox" by Dr Kate Rheaume-Bleue is well worth a read for information about the health benefits of K2.
I also take omega 3's and vitamin D3, both supposed to be helpful for the heart. I get those prescribed. And I take CoQ10 which is also supposed to be helpful for the heart