I hate to be a buzzkill, MinerPhill03, but there may be one major flaw in your plan, in that you probably cannot fool your brain into thinking it is having a heart attack.

Physiologically speaking, your brain has no trouble at all with distinguishing between reality and imagination. It is your consciousness that has this difficulty during dreams, because you cannot remember that things are not real; your brain is actually running the show, and doing so while fully based in reality.

Also, your brain, in the end, is you, so you would have to somehow trick yourself into believing you are having a heart attack, which would be a pretty neat trick... especially because, while lucid, every part of you has no trouble with distinguishing between reality and imagination.

Finally, if you actually did manage to trick your brain into having a heart attack, it might just oblige you by triggering a real heart attack, and this is never a good thing.

On top of all that, there really isn't any correlation between increased brain activity and time dilation. That the mice's brain activity increased does not necessarily mean that they experienced an increased passage of subjective time (indeed, mice don't experience that passage of time at all, now that I think of it).

Feel free to ignore all of what I said, though, because some things are just fun to think about!