First off, I don't remember ANY of this...
If it's any consolation (and please don't take this the wrong way, I've had a life long heart defect that's pretty unique and not commonly seen in people over the age of thirty (in fact, there's no one over the age of 45 that has it because they couldn't fix it before the '60's...)
I had a pretty rough time my first month after the surgery. I was on a ventilator and spent most of my time under pretty heavy sedation. The time I wasn't as sedated I communicated with my fiance (we're married now) through a chart she made up of the letters of the alphabet.
My memory starts about a week or so AFTER they removed the tube, that's about five weeks or so after surgery, and even then it's a bit fuzzy.
Talk to your surgeon about your concerns. There are a number of things they can do to alleviate them, including, possibly, an anit-anxiety medication.
The last thing they want is for you to walk into that hospital in a panic attack, it won't help you before surgery, it won't help you during surgery, and it won't help you afterwards.
A comfortable patient heals faster. Mental attitude is really important and they will do whatever they can to make sure you're comfortable and not agitated.
Mind you, I don't remember ANY of this at all, nothing!