I'm going in for my second c-section in six days. :-)
Basically what happens is you go in a couple hours prior to surgery to get prepped, monitored, get your b/p ect done. You with get a catheter, sometimes before the spinal, sometimes after. You go into the surgery room and you sit on the edge table. The anesthesiologist comes in and has you lean clear forward to open the space between your vertebrae (a nurse helps you and distracts you). Then you feel a pinch, a tiny burn, and your spinal is done! They lay you down, and put a drape up right at your chest line to keep the surgical area sterile. Your arms will be to either side of you. The anesthesiologist will monitor your vitals throughout. You'll have oxygen on (standard), I.v. Running fluid, ect. The doctor will come in and poke you with a small pin from your chestline down to make sure the spinal is properly working. Your support partner well be brought in to suit with you and surgery will begin.
They make an incision at your."bikini line", take baby out, make sure everything looks good, take out the placenta, and sew you up! When they take baby out you'll feel your body rocking because someone will be applying pressure on your upper abdomen to encourage baby to pop out of the incision. You may throw up because of your stomach getting roughed up a tad.
Usually from incision to birth is around 30 mins, then birth to closure is 30ish mins. You go to recovery afterwards for about an hour then to your permanent room if all is well :-).
What type of heart condition do you have? I have one too, but my docs have yet to discuss whether I will be able to give birth vaginally yet.