I've had palpatations on and off for about 19 years and nothing has ever come of them. I know just how miserable it feels, and how it can so quickly send you into a panic, but if you had all the tests done that needed to be, and all was fine, try not to worry over it too much. It's a normal occurance in almost all people, some notice it and others don't. Unfortunately, we are among those that do feel them and let it bother us. You hang in there and remember that I've had them alot and sometimes they have been really bad, back to back to back ones at times, and nothing bad has ever happened to me.