Well, being that the rapid heart beating and the hypnagogic hallucinations stopped simultaneously, this probably was just another hallucination.

If this was a hallucination, then yes, it's normal. Even if it weren't, I don't think that the heartbeats were as major as you remember, it just seemed that way due to panic(which is totally normal the first WILD attempt).

Go for it again tonight if you'd like, and calm down. Hallucinations are only hallucinations, don't worry.

Good luck, welcome to DreamViews.
^.^