Congestive heart failure (CHF) occurs when the heart is unable to provide sufficient pump action to maintain blood flow to meet the needs of the body.
There is a back up of fluid into the lungs that causes them to swell (pulmonary edema). This results in an inability to breathe and can be fatal.
Image Source: NHLBI
source:
All above Videos courtesy of St Jude's Medical
Image Source: Clotbuster Archives
This is a chest x-ray of someone with congestive heart failure (CHF). Both lungs are filled with fluid.