I had a similar procedure about 1 year ago.
In my case they were zapping a nerve in the heart (which was screwing up my heart’s rhythm), using a catheter.
But my experience was much the same as Oakminster, so I’ll just mention the things that were different.
In my case I was asked to shave my groin myself. Then, on seeing what a poor job I’d done, the nurse came and shaved the area again.
But seriously, it was the crappest razor I’d ever seen. (Might be worth bringing along a decent wet razor).
I was awake for the whole procedure but “blissed out” on something, and my recollection of most of it is vague. But towards the end my alertness rose and there was pain at that point. Not huge pain – ironically it was somewhat like heartburn.
This won’t apply for you (though you may find it interesting), but they had control of my heart rate and had to slow and speed my heart as part of the procedure. Which felt very weird.
After the procedure, for some reason the catheters had to stay in for an hour or two, which was annoying more than anything because it meant they wouldn’t let me sit up, because I could bend the catheters.
For me, the most painful bit was after removing the catheters. They had inserted a total of six into my groin and just pressing on the resulting wound would be insufficient to stop the bleeding. So they had a belt and an inflatable plastic ball thing that could apply strong, sustained pressure.
A couple of quite hot nurses actually applied this device and I mention that because it was extra motivation not to scream like a little girl when the ball inflated. Which I (just) managed not to do.
The ball was there for another half hour or so, though the pressure of it is gradually reduced over that period.
Oh, and for about 10 days after the op, I had at least one migraine a day. As someone who’d only had 4 or 5 migraines in my life before that point, this was quite worrying for me.
But I haven’t had one since then, so it was probably just a reaction to one of the drugs (as well as “happy drugs”, they also have to thin and thicken the blood), or just the stress of the whole thing. Either way it’s a very rare side effect.
Anyway, good luck, hope I haven’t made it sound too scary. It’s really not that much to go through