Best of luck to both of you guys. Thankfully, they have made some big strides in medicine over the last couple of decades.
A few weeks ago, my wife was in the hospital for a racing heart. It was running at 230 beats/minute when the EMTs showed up. Being 7 months pregnant, they had to be very careful how they treated it. She spent a couple of days in the hospital. It turns out she has basically an electrical short in her heart that they can fix with a relatively simple procedure. Once she has recovered from her C-section, they will be taking care of it.
Glad it turned out okay, it was pretty scary to see my wife in the ER, surrounded by 8 (EIGHT!) cardiologists and her OB/GYN. I watched her BP go as low as 60/40 and really got worried. Thank god for medical technology today, or she might not be sitting next to me right now.