What is the definition or description of: heart failure?

Abnormal Pumping: Heart failure is a complex set of conditions in which the heart "fails" to pump a normal amount of blood with each beat. This can be due to poor squeezing function (systolic heart failure) and/or a stiff heart incapable of filling normally (diastolic heart failure). Common symptoms include swelling and trouble breathing, particularly when laying flat or exercising.

Weakness of heart.: CHF is primarily caused by an issue in the heart that prevents it from being able to supply your body with the oxygen it needs. This can be caused by weakness of the heart muscle, insufficiency of a valve in the heart or a rhythm disturbance that disrupts the forward flow of blood from the heart.