Heart
failure is a clinical syndrome in which the heart fails to maintain an adequate output, resulting in diminished blood
flow and congestion of the circulation in the lungs, the body, or both, depending on which side of the heart is affected. In left-sided heart
failure, the left atrium and ventricle are not adequately pumping the blood returning from the lungs to the rest of the body. The blood vessels in the lungs become engorged, and fluid can fill the lungs. In right-sided heart failure, the right atrium and ventricle are not adequately pumping the blood from the body back to the lungs to become oxygenated. The blood backing up in the body may cause edema (
swelling of the legs), or blood congestion in other organs. Common causes of heart failure are heart attack, hypertension, coronary artery disease, and rheumatic heart disease.
The main symptom of left-sided heart failure is shortness of breath, which often occurs during mild exercise or climbing stairs. This may result in periodic attacks that frequently occur at night while the person is lying flat. As heart failure progresses, shortness of breath becomes more difficult to relieve. The principal symptoms of right heart failure include swelling of the ankles and occasional tenderness in the right upper part of the abdomen due to swelling of the liver. In advanced stages swelling becomes more severe, and fluid may collect in the abdomen. Treatment of heart failure depends on the underlying cause. Restriction of salt and water intake, and drug treatment with diuretics (which promote urination and removal of fluid), and angiotensin-converting enzyme inhibitors (which control the body's fluid load) are the mainstays of treatment.