OK--I'm going to encourage you, I hope.
My husband has been through enormous, scary, horrible things related to his heart problems. He's been in your mom's position quite a few times. He's had three valve surgeries, two lung surgeries, has two mechanical valves, has a pacemaker, has congestive heart failure, has a terrible terrible lung problem called pulmonary hypertension, has renal failure from time to time, chronic and acute. He's also had several infections, bacteremia, and even a recent bladder one. There isn't enough room here to post all of the problems he's had over his 28 years battling his heart and lung problems and they are all difficult. His history is three pages long in a small font.
He's had every conceivable test including the Swan. For that, in his case, they left the Swan in for two days. That doesn't happen very often, and won't happen to your mom either. But they had to do that in Joe's case. He's had echos by the dozens, TEEs, a thransthoracic echocardiogram, all kinds of scans, so many blood tests that it would be impossible to count. He's had tubes and catheters running into and out of every orifice. His body looks like a train switchyard with all the scars.
He's 74 years old, and he's still here. Granted, he requires much medical management, and actually burns out many of his doctors. So we try to sort of rotate them around to give them a break
As long as his docs can head him in the right direction and keep his little train on the narrow tracks, his body heals from all these things. It may take some time, but that is what the body does the best, slow and steady healing.
The trick to all of this is to not give in to any of it, never give up, hang on by your fingernails if you need to, and make very, very sure the doctors taking care of your mom know what they are doing.
Your mom will do fine. She's having rocky times right now, but don't let negative thoughts cloud your mind. Perhaps with some med changes, she'll be as comfortable as possible until her surgery date.
Just hang in there and your mom too. Be her cheerleader, put a smile on your face and give her a big hug and a kiss, and tell her that it will all get straightened out.
And I don't want you to think your mom's problems will ever be as bad as Joe's. He's much more complicated than most valve folks. He wasn't supposed to live past 50, but he did.