Can anyone tell me whether the terms "palpitations", "flip-flop", and "flutter" are interchangeable. When I think of palpitations, I imagine them to be a rapid heartbeat that is persistent for a period of time, and not just a couple of beats that are wacky. A flip-flop seems to me to be where the heart gives two or three solid thumps, while contrariwise, a flutter is just a few light rapid beats. What causes the differences? Are their different implications?