Heart failure is when the heart is unable to pump blood around the body well enough to meet the needs of the body. This is usually because the heart has become too weak or too stiff. There are many causes for this, which include heart disease and high blood pressure. It does not mean the heart has stopped working, but that it is not working as well as it should be, and may need some support.
As the heart cannot pump blood as well as it should, it can cause fluid to build up in the lungs and lower legs, causing breathlessness (dyspnoea), swelling of the lower legs (lower limb edema), and orthopnoea (breathlessness when lying flat). Heart failure is a long-term condition. Treatment for heart failure aims to control the symptoms, and varies depending on what is the cause of heart failure.