Look, heart surgery is scary. It is.
Hopefully you have a medical team you are comfortable with. If you don't, you are absolutely allowed to seek a second opinion. I have every confidence in my medical team. This is paramount.
Having found a doctor you have confidence in, if your doctor tells you you need to have heart surgery, you need to do it. I'm pretty sure no surgeons are cracking chests just for funsies, a serious heart condition is no joke, and you can't ignore it away. Whats more scary than heart surgery? Dying. Dying or becoming so completely debilitated by your condition that you can't even walk up a small flight of steps without needing to sit down and rest, and you end up being a burden on your friends and family, who, assuming you are lucky like me and have a wonderful family and circle of friends who are there for you, will take care of you - they will do it without complaint, but do you want to do that to them? No. This is one of those scenarios where you just need to suck it up, pull on your big girl/big boy pants and get on with it.
The good news, at least in my experience (and experience may vary so don't get all mad at me if this isn't the case for you) IT'S NOT THAT BAD. Seriously. What follows is my experience, or at least how I remember it since I was FLYING on weapons grade painkillers.
Despite waking up post-op feeling like a freight train ran me over, then backed up, my first thought was "Yay! I'm not dead!"
Then I thought "get this fucking breathing tube OUT. OF. ME"
Some time around now I also thought "Did a cat take a shit in my mouth?".
Once they removed the breathing tube (which is not a nice experience but it was over in a flash) I began asking for water. They wouldn't give it to me. Not ice chips. Not even a wet sponge. . For good reason. After anesthesia, they make you wait several hours before giving you any liquids (you won't want food, so that's a non issue. You'll want a drink tho, due to aforementioned cat shitting in your mouth) when they DID finally give me some water, despite attempting to adhere to the instructions to only take tiny sips, I still managed to vomit all over myself, which is frustrating when all you can do is push a button and call a nice ICU nurse who will smilingly clean you up because she is an angel sent from heaven and you are a mere mortal who can barely move.
The morning after surgery when the anesthesia had all worn off I became more aware of the situation happening around me. The drainage tubes coming out of my belly like some macabre real life Geiger sculpture, the wires connected to my heart (in case I needed a jump start) the catheter, the IV. All very sexy, and somewhat uncomfortable. Some time around now, they came in and announced that it was time to stand up. My first inclination was to tell them to go piss up a rope, that I had a HEART CONDITION and I was very very TIRED and it will HURT and NO. But with the help of a couple of nurses, and a bed that tilts you up like one of those old people recliner/ejector seats, they got me upright, and I managed to shuffle about 20 feet. While not a pleasant experience, it was nice to know that I COULD get up and walk.
The first day or so out of surgery are honestly a bit fuzzy, because they kept me doped to the gills to keep the pain at bay. I vaguely remember X-rays, and at some point I was moved out of ICU into a room in the recovery ward. Once in there, I mostly just slept, woke up, took more pain meds, and slept more. Occasionally people come in and talk to me about stuff, I had a few visitors, and then I slept more.
At some point they wanted me to start eating again. My experience is that hospital food is universally grotesque (even the ubiquitous hospital Jello. HOW do you fuck up Jello?), and since my diet was never really an issue (as far as salt/fat blood pressure/cholesterol related issues) , I had my Dad bring me stuff - I would assume that unless you're on some heavy diet restrictions, you can probably have folks bring you stuff that doesn't look like it was made by people who hate food and want it to be punished. I didn't have much of an appetite, I only wanted fruit salad (real fruit salad, not that canned crap) and pudding. Even if you don't want to eat, you have to eat. Your body needs fuel to heal itself.
As I mentioned, among the lovely things adorning my body, was a catheter. (warning: possible TMI) The catheter was removed with the notation that if I didn't pee by 10pm, it was going back in. Having NO interest in having a catheter re-inserted, after the nurses assisted me to the throne, I sat there. I sat and sat and sat. Nothing happened. I had to pee. I WANTED to pee, but I couldn't pee. There was nothing wrong with me, I can only assume it was the pressure of a looming deadline that caused my bladder to become a shrinking violet. During my epic sit, both my legs fell asleep, to the extent I had to be hauled up off the pot by 2 nurses, and practically carried back to my bed. Definitely one of the more glamorous high points in my life. Fortunately, I was able to finally pee just before the deadline and was able to remain untethered. By that at least, there were still the drains and wires.
The removal of the drains and wires I *think* came 2 days post op? Painless, but the feeling of the wires coming out was really unsettling. While we are aware of our hearts, and can feel our heartbeats, the feeling of something inside you actually TOUCHING your heart is truly bizarre.
Once all the tubes and wires came off it was really pretty much smooth sailing. I still slept a lot, but I could also get up on my own, and would go on walkabouts around the ward. I also was able to put on my own clothes. I brought my pajama pants and thermal shirt and fuzzy slippers which were SO much better than bullshit peekaboo hospital johnnys and those useless fucking beige socks with the grippy rubber dots on them that will inevitably work their way around to the top of your feet within five paces because they SUCK.
I was pretty much feeling ready to go home after 5 days, I missed my cats, I missed my house, I missed wifi that wasn't crap. I ended up getting sprung after 7 days, since my INR took its sweet time getting up to speed, but were it not for that I would have been home in under a week.
So thats pretty much what I recall of the experience. In the great list of awful experiences in my life, it doesn't even crack the top 5. If you're having surgery and you're scared, that's ok, but remind yourself that you're probably tougher than you think you are, you've got this.