I wish you a speedy recovery! Being dead for 30 mins then coming back with no brain problems is a miracle! And I've heard that dying is just like going to sleep, it's weird sounding but many people have said the same thing. :S
Coming in a bit late and saw your updates, glad you're doing better and hope things continue to improve and get back to somewhat normal.. Take care of yourself, that was a scary experience for anyone, glad you made it!
Damn. Still, if you do find out anything that could indicate why, you should definetly do something about it.
I've already altered my diet and cut out salt, fat and cholesterol. I expect my restrictions to loosen up after a couple of months. Funny thing is, I'd already started to change my lifestyle before this happened.