Interesting. Dh has the opposite problem as you -- he has bradycardic episodes, wherein his brain is supposed to be telling his heart to speed up and accidentally sends the slow down signal, causing his heart to beat even slower, sending less blood to the brain. This usually ends up with him passing out, which has been a problem if he is carrying a small child. He is managing it fairly well with diet so far and has been told by his cardiologist that it may spontaneously go away over time (WTF? Um, ok.).

Anyway, I feel for you (and seamus_mcnasty too), funky heart stuff is no fun!