Don't think it's progressive. In my case, it came on as a result of being weakened by afib and the TURP with all the fluids employed.
Don't think it was progressive in my Dad's case either. In grandmother's case, it probably was, as she had swollen legs a long time before she got CHF and died.
So many things that you buy have tons of salt in them. My wife is non gluten. It's virtually impossible for us to go out to eat any more: ice cream and yogurt places. That's about it. One small chain in Columbus, OH caterers to both non gluten and low sodium. A couple places around here say they do non gluten, but they have virtually nothing that I can eat. At the bowling alley, there is absolutely NOTHING below about 2,000 mg of sodium, FAR above what I allow myself now.
Lots of people get their ejection fraction back to normal after CHF. Trick is keeping it there with no sodium and exercise.
Ralph