Congestive heart failure happens when your heart gets too weak to pump blood from the lungs out to the body. Pressure builds up in the heart which puts pressure on the blood vessels of the lungs. This will lead to leakage of the vessels and the fluids build up in the air sacs of the lungs. This condition is called pulmonary edema.
Pulmonary edema occurs when fluid builds up in the lungs making it hard to breathe. It may start out as running out of breath easily but if left untreated (both conditions) symptoms get worse over time.
