WHOA Mary!
Take a few Deep Breaths and think calming thoughts.
Here's a list of Medical Modifiers in increasing order of severity:
NO / None
Trace
Mild
Moderate
Severe
Critical
Usually MILD is when a Doctor says "By the way, you have such and such. We need to monitor that to see if it progresses. It is NOT a problem at this time." or some such message...
Most surgeons do NOT make Aortic Valve Repairs, only replacements. It sounds like your Aortic Valve leakage is NOT a major concern and certainly did NOT justify replacing the valve. (My understanding is that Aortic Repairs do NOT have a good track record).
OK, take a few more deep breaths and get a good night's sleep! It sounds like your new Cardio is on top of things and will take good care of you.
Note that Depression (and Anxiety) are common after OHS, not to mention being on an Emotional Roller Coaster so try to turn your 'sensitivity control' down a notch or two and let your body recover at it's own pace.
Also note that A-Fib (and A-Flutter) are quite common after OHS and are generally considered to be benign (did your Cardio Yawn?). They're not fun, but once you are convinced they are not dangerous, it is easier to 'ride it out' without getting overly anxious. Call your Cardiologist if / when you experience anything 'unusual'.
You WILL get stronger (and braver
'AL Capshaw'