Re: rapid heartbeat....really freaked out
John, calm down. A rate of 105 is NOT a dangerously fast heartbeat. It's quite low, in fact. The heart can sustain a heart rate of 200 and even higher for a long time without difficulty. In fact, a normal resting heartrate is between 60 and 100 so yours is only slightly high - nowhere near high enough to kill you.
A heartbeat of 105 will do absolutely no damage. Have you had a lot of caffeine today? Have you drunk plenty of water? Drink some water and lay off the caffeine and you should be fine.
If your resting heart rate continues to stay above 100 for a day or two, see your doctor, but I promise you're going to be ok.