HAHAHAAHAHAHAHA!!! You can never really tell.
As I posted on this site, last October I had a mild heart attack. I had had a complete physical, only had minor elevation in cholesterol and BP. Then Boom! My right artery was 99% blocked. Who knew?!?!!
Live everyday like its your last. Have fun and take some chances. After all, what does it really matter if you've never really lived????????