Heart condition and labor

So I’m nervous, I’m 38 weeks and I have a heart condition worsened with pregnancy ( we didn’t really know about it before I got pregnant but I always had a feeling something was going on) so I get very rapid heart rates that make me black out and could cause worse but thankfully it’s not gotten to that point and I’m supposed to have a baby soon and I’m worried about labor and my heart I’m not sure if I’ll be able to handle it or if something can go wrong, has anyone else experienced this and how did it affect labor and delivery I actually have a. C section scheduled because baby was breech but he turned so I’m not sure if I’m going to cancel it or if it’s safer at this point and my doctor won’t talk to me till the day before my scheduled c section so that’s fun 🤦🏻‍♀️