This is, of course, highly variable, but generally speaking the pay for EP is greater than non-invasive but somewhat less than interventional. As previously stated, there is rarely such a thing as an emergency case that'll get you up in the middle of the night although I've seen this happen in unusual and dramatic circumstances.
With current technology and techniques, some EP procedures can be lengthy, verging into the 4+ (sometimes 6+) hour range. That has to be acceptable to you. (It isn't to me.)
It's a fairly esoteric field, even to non-EP cardiologists who frequently want nothing to do with complicated EP problems. In that respect, you are a true subspecialist, working in areas that nobody else has the foggiest clue about. Every cardiologist has had some experience with the cath lab, reading cath films, etc. Not every cardiologist has any quality experience in the EP lab, interpreting EP studies, etc.
Really you just need to spend good quality time in an EP lab and see if you are interested in what is going on.
