What is the longest someone not treated lived with congestive heart failure?

Historical data: In the old days, the oft quoted survival statistic for CHF (since there was no treatment) was a 2 year 50% survival. Obviously, that takes all comers - some forms are very mild and this wouldn't apply. Moreover, modern treatment has completely changed all that.

Impossible to say: You would need to know all of the people that have ever had heart failure and follow them until their death. As you can see this would be an impossible undertaking.