Congestive heart failure (CHF) is a condition caused by a weakening of the heart muscle that prevents it from pumping efficiently. In general, heart failure is a chronic condition where the heart does not pump enough blood to meet the body’s needs. This causes symptoms such as fatigue, breathlessness and fluid build-up in the legs and feet. Heart failure can be due to various cardiac diseases. These include coronary artery disease, which can weaken the heart muscle because not enough blood reaches it, and uncontrolled high blood pressure, which stresses the heart muscle by requiring it to beat against higher pressure. Abnormal heart valves that do not fully open or have significant leaking can also overwork the heart. Other diseases that require the heart work harder, such as anemia, diabetes mellitus, lung disease and thyroid disease, can also cause heart failure. Once heart failure occurs, the body may respond by producing hormones and chemical substances to try to get the heart to beat stronger, but adversely affect the condition. Congestive heart failure is a progressive disorder that must be controlled not only by treating the heart, but also the circulation, the lungs, the neuroendocrine system and other organs. If there are other conditions present, such as abnormal kidney function, hypertension, vascular disease or diabetes, it can be even more difficult to treat.