Edgar Allan Poe had the same disease i think, he would have fits and would appear to be dead, all the blood moved from the surface to protect his organs therefore appear blue and his breathing was very laboured. If you read his books most of them have an underlying theme to being buried alive
My next door neighbour had to dig up some graves when they built a bypass beside me and he dug up one grave which looked like the person had a bit of a struggle in the coffin, imagine that waking up in a coffin knowing you can't get out.

I heard that some people ask to be buried with their mobile phones incase they are buried alive!!!!