"today my family physician informed me I should meet with a Cardiologist to explore the findings from recent tests
about me needing a heart valve replacement
if done what does the FAA do?
do I have to sell 777H?"
If it were me, I would get the heart valve if really needed, get yourself well, then find a doctor to give you a Basic Med assuming your insurance will allow Basic Med which some don't. A lot of heart valves are now replaced with catherters so make sure you find the doctor that has done the catherter replacements; not the open heart surgery routine. Once you start the FAA route, there is no going back you will be too old to fly again with all their run arounds.