Teddy
I'm thinking you are over thinking what your thinking about this operation.
Not knowing your condition, other than you statement that your "fair" and I'm not a med student,, but most of the people I know, that have had open heart are up running around in a couple weeks or less...
My father lasted over 20 yrs and my father in-law 15 yrs.
Have another talk to your Doc's..
You need to get a bunch of CAN-DO back in your altitude..