I had an ablation (no ICD) at 40. The medication doesn't knock you out, but it does put you in sort of a twilight state...I SERIOUSLY wouldn't have cared if a Mack truck rolled through that room! It was a long procedure (according to my waiting husband), but it didn't feel long to me...the twilight, I guess. I wasn't exactly aware of what was going on, but I wasn't unaware either...truly, the medication is great stuff.
The biggest thing for me was how much BETTER I felt afterward. While they were rolling me to my room, I realized immediately just how much effort I had been spending trying to keep my heart rate straight. It was a WONDERFUL feeling to just be aware that I felt "normal" again. I kept forgetting that I couldn't bend at the waist afterward...the hubs ended up basically sitting on my thighs, as I was scaring him.

Couldn't help it, though...I felt SO GREAT and the relief was palpable. The entry point was a little sore later in the evening, but as of the next morning, I was back to normal, only much much better.
I resisted that procedure out of fear...cried like a baby when they took me down, just knowing that something would go wrong and I'd never come back...but now I wish I had done it
long before I did. It has completely changed my life, to be sure.
I sincerely hope that your daughter has as good an experience with this as I did. Please come back and update us?