Heart failure, also called congestive heart failure, is a disorder in which the heart loses its ability to pump blood efficiently. The term "heart failure" should not be confused with cardiac arrest, a situation in which the heart actually stops beating.

Heart failure is almost always a chronic, long-term condition, although it can sometimes develop suddenly. This condition may affect the right side, the left side, or both sides of the heart.

As the heart's pumping action is lost, blood may back up into other areas of the body:

• The liver
• The gastrointestinal tract and extremities (right-sided heart failure)
• The lungs (left-sided heart failure)

With heart failure, many organs don't receive enough oxygen and nutrients, which damages them and reduces their ability to function properly. Most areas of the body can be affected when both sides of the heart fail.

The most common causes of heart failure are the chronic cardiovascular diseases hypertension (high blood pressure) and coronary artery disease. Other structural or functional causes of heart failure include the following:

• Valvular heart disease
• Congenital heart disease
• Dilated cardiomyopathy
• Lung disease
• Heart tumor

Approximately 2 out of every 100 people between the ages of 27 and 74 have heart failure. Heart failure becomes more common with advancing age.