How to mount LCD over working fireplace/chimney?

We are looking to mount our TV over our fireplace. The fireplace works, and there is a chimney too. We are going to buy an LCD b/c we have a plasma and have heard that they don't do well with heat. I am just wondering how to hide the cords. I don't want them showing but I am scared that we may ruin the chimney. Any suggestions? Thanks!