The purpose of my post is to address your concerns. Firstly, ANYTIME you enter a lab or OR, your life is at risk. But consider the risk. Talk to your electrophysiologist, and express your concerns. Ask him point blank about his successes and failures. He will not be offended. If he is, find a new one.
Pain... yes, some people report pain. Some say it the procedure hurt a lot, and would never submit to it again. The electrophysiologist I chose used general anesthesia whenever possible so his patient's comfort was not a factor, and allowed him to concentrate on the task instead of a squirming patient. I felt nothing, and remember nothing. I barely made it awake to the Cath. Lab when the initial hypo of Vallium hit me on the way down. My whole procedure was a pleasant experience because of that. So ask well ahead of time if the that can be done for you too, or find a physician who uses general anesthesia during his procedures.