Squeak,
I have been there, I understand, it is frightening. It repeated from time to time over a period of three years.
The time was stressfull, it was in the middle of my seperating with my wife. I was shown some methods of controling the heart beat. And I do not mean for you to handle your won problem -- get help -- get into understanding YOU!

I agree with "get to a doctor". I did get my heart under control, but not before I realized I was the cause. I guess you might say, it's not what my heart is doing to me, but what I am doing to it!!