SN explain that Heart failure is a condition in which the heart can not pump the amount of blood the body needs. Heart failure does not mean that the heart has stopped or is about to stop working. It indicates that the heart can not pump blood the way it should. It can affect one or both sides of the heart the weakening of the pumping capacity of the heart causes: Accumulation of blood and fluid in the lungs Accumulation of fluid in the feet, ankles and legs called edema Tiredness and shortness of breath The most common causes of heart failure are coronary artery disease, high blood pressure and diabetes. It is most common in people over 65, African - Americans, overweight people, and people who have already had a heart attack. Men are at greater risk than women.