M.T.
Def discuss this with your cardiologist or doctor right away and dont wait unless he is already aware......it could be a sign of a serious condition worsening not to scare you butCHF is nothing to fool around with......esp if you have the Dx that you stated.
Every well swells in the extremeties in the heat.....but not to the point of which I understand yours.. Edema is a warning sign for those who have heart failure.....right and left side heart failure shows different symptoms....
Call you doctor and get it checked out........A fib can convert to a more serious rhythm...
RN