My heart raced for 2 hours one night. After spending 2 hours scared and certain I was dying, I got out of bed went to my computer and typed into a google search "how to make a racing heart stop". I came across an interesting article (link above) about what has been learned from divers....I quickly got a very cold rag layed down in bed and placed the rag on my face and neck. Within seconds the racing heartbeat stopped! I couldn't believe it and finally fell quickly asleep for the rest of the night.