Failure, heart: Inability of the heart to keep up with the demands on it and, specifically, failure of the heart to pump blood with normal efficiency. When this occurs, the heart is unable to provide adequate blood flow to other organs such as the brain, liver and kidneys. Heart failure may be due to failure of the right or left or both ventricles. The signs and symptoms depend upon which side of the heart is failing. They can include shortness of breath (dyspnea), asthma due to the heart (cardiac asthma), pooling of blood (stasis) in the general body (systemic) circulation or in the liver's (portal) circulation, swelling (edema), blueness or duskiness (cyanosis), and enlargement (hypertrophy) of the heart. There are many causes of congestive heart failure including: (1) coronary artery disease leading to heart attacks and heart muscle weakness, (2) primary heart muscle weakness from viral infections or toxins such as prolonged alcohol exposure, (3) heart valve disease causing heart muscle weakness due to too much leaking of blood or heart muscle stiffness from a blocked valve, and (4) hypertension (high blood pressure). Rarer causes include hyperthyroidism (high thyroid hormone), vitamin deficiency, and excess amphetamine ("speed") use. The aim of therapy is to improve the pumping function of the heart. General treatment includes salt restriction, diuretics (to get rid of excess fluid), digoxin (to strengthen the heart), and other medications. Specific treatment of congestive heart failure needs also to be directed toward the specific underlying cause of the problem.