The heart is a muscle. It squeezes and relaxes with each heartbeat to pump blood around the body.The normal healthy heart is a strong, muscular pump a little larger than a fist.
The body depends on the heart's pumping action to deliver oxygen-and nutrient-rich blood to the body's cells. When the cells are nourished properly, the body can function normally.
With heart failure, the heart muscle becomes too weak or too stiff to work properly. The heart cannot pump efficiently enough to meet the body’s need for blood. Contrary to its name, heart failure does not mean the heart has failed completely. It is a term used to describe a heart that cannot keep up with its workload due to which the body may not get the oxygen that it needs.
Heart failure symptoms usually develop over time as heart becomes weaker and pumps less blood than the body needs. Initially the body tries to compensate in different ways which may mask the problem but does not solve it. Heart failure continues and worsens until these substitute processes no longer work.
The body's compensation mechanisms help explain why some people may not become aware of their condition until years after their heart begins its decline (It's also a good reason to have a regular check up with a doctor). Heart failure is called congestive heart failure when fluid builds up in various parts of the body. Heart failure usually results in an enlarged heart.