Good Evening MGary--
I wanted to offer support and reassurance. Days after hitting the big 50, I had my aortic valve and ascending aorta replaced in January 2020 and can completely relate to the freaking out. I don't think anyone who is ever confronted with open heart surgery (regardless of age or circumstances) doesn't freak out. So don't let the freaking out freak you out
Unfortunately, the shock and following anxiety is normal--but it still sucks!
Please let me reassure you, OHS is NOT the end of the world. As many have testified to on this site, you will make it through and come out stronger on the other side (both physically and mentally) and be working hard in grad school before you know it.
I too thought it was strange to only meet with my cardiac surgeon once prior to surgery. It was routine at the facility (IMC Hospital) to have all the testing you describe done just days prior to the surgery. I used google, the AHA site, Mayo Clinic, Cleveland Clinic, JAMA, Journal of Thorasic Surgeons, and similar sites to research and learn as much as I could. There is really good information out there from very reputable sources.
Then, I put my thoughts to paper and got help from my surgical team and my primary care physician. I had (literally) five pages of all kinds of questions for them. I sent the list off to the office and the surgeon personally answered them. I would hope that your surgeon and their team would offer a similar service for you. I think your surgical team should provide reassurance and guidance through the whole process--they are the experts and that is why you are paying them
. Not just to give you a nice piece of needle work, but to help with the whole process. The medical profession has fantastic, amazing procedures and processes to fix our hearts and get us healed-up.
At your young age and (assuming) good health, the surgery will be an experience, but TOTALLY doable. I had surgery on a Monday and had to walk out of ICU upstairs to the cardiac floor at 8:00 a.m. the next morning. (I many never forgive cardio rehab guy Toni for making me do that!) I was home resting on the couch waiting for home health care (at my parents house) that weekend.
Sorry, I seem to be rambling. (But I can totally relate to the anxiety struggles.) Just know that if you have any questions that can help ease your mind, provide been-there-done-that insight, or anything else--just reach out!
God Bless, keep safe, and take care! You are going to do great!