I remember this book I read a while ago, but I can't remember its name. It's part of a series of I think 3 books. Each book has a picture of an eye on the cover.
The story starts with the main character who is a kid somehow teleporting to another world over a continental divide. He also had heart issues. In the other world, magic was possible, everyone spoke English, they told stories about our world, and his heart issues stop.