Hi Bill
Welcome and congratulations on your recovery and return to the lifestyle of a 25-year-old!
I'm about your age, but had surgery > 7 years ago. I had been perplexed by observations similar to yours. Now I'm merely curious...which is probably good, because being perplexed for the long term is at least useless and probably bad for me.
Here are a couple of other threads in a similar vein:
http://valvereplacement.com/forums/showthread.php?t=23046
http://valvereplacement.com/forums/showthread.php?t=25500
I had surgery in January (02), and I go into semi-hibernation in winter, so I'm not sure exactly when I turned the corner on recovery. I had my annual cycling vacation 9 months after my surgery and guesstimate I was 85-90%. The following summer I seemed to be at full recovery. Since then I haven't gotten any faster or slower (a bonus for an old guy).
The good news for me is that I don't take any meds other than daily aspirin, I have no complications or activity restrictions, my valve performs flawlessly and my heart has returned to normal dimensions. Pre-surg, I had been deteriorating at a pretty rapid rate, most likely on track to be in heart failure by age 50 w/o surgical intervention. Now, I am enjoying an active life with my family and am on track to outlive my 401(K)
Regarding those two threads: They're ONLY two data points, so I wouldn't draw any conclusions from them. I also recall that I've recently read a thread by a MV repair patient who was kicking serious @ in cardio competition...but can't recall enough of the detail to search and locate.
I wish you the best and hope you continue to make improvements. If that's not in the cards, I hope you continue to enjoy your trail running, skiing, surfing, etc. with the rebuilt engine you've got.
Cheers,