Things like this always crack me up! If you've ever had a lucid dream then you know what "more real than real" can mean. Seeing as how I've done this many times (and without being near death as far as I could tell) I know what effect it might have on a person. Whenever it happens to me, I wake up estatic! and the "high" lasts all day and moreover becomes a part of me as a person.
Yeah. It's amazing. Hands down.
No. I don't think it has anything to do with "Heaven". Just another "God of the gaps" case of something cool and new happening, and people cramming it into they're preconceived notions.