What is congestive heart failure?
Congestive heart failure (CHF) (also called heart failure) is the inability of the heart to pump blood effectively to the body, or requiring elevated filling pressures in order to pump effectively. Congestive heart failure occurs when the heart is unable to pump blood effectively throughout the body. The term congestive is used because lung congestion causes some of the main symptoms of heart failure. Heart failure does not mean that your heart has stopped working completely. It means that
the heart is not pumping as strongly as it should. As a result, some of the blood that is normally pumped out of your heart backs up into your lungs and other parts of your body. With congestive heart failure, your body tissues and organs may not get as much blood as they need.
Congestive heart failure is a condition sometimes referred to as pump failure. The muscle of the heart fails to properly pump blood through the circulatory system. Because blood flow to the kidneys is reduced, they retain sodium and water. That water enters the circulation, and the excess volume accumulates in the lungs, abdominal organs, and the feet and ankles. There are many different ways to categorize heart failure, including the side of the heart involved (left heart failure vs. right heart failure) or whether the abnormality is due to contraction or relaxation of the heart (systolic heart failure vs. diastolic heart failure). Heart failure can be classified as either a pump problem, where not enough blood is squeezed out of the heart to the body, known as systolic dysfunction, or a filling problem due to a stiff heart, known as diastolic dysfunction. Systolic failure can lead to blood backing up into the lungs, causing shortness of breath, also known as pulmonary edema. Problems with the heart's pump function can also create problems for the rest of the body, such as kidney problems, liver problems, fluid retention and lower extremity edema. Even when the heart's pump function is normal, if the heart is thickened and stiff, congestive problems can arise. Specifically, if it takes higher pressure to fill the heart, then the lungs again can become full of fluid and shortness of breath can occur. Though heart failure may be limited to systolic or diastolic dysfunction, having one type often leads to having the other as well.
The heart consists of four chambers: the right atrium, the left atrium, the right ventricle, and the left ventricle, and four major valves: the mitral valve, the tricuspid valve, the aortic valve, and the pulmonary valve. Atria are relatively thin-walled chambers that receive blood from the circulatory system and from the lungs. Ventricles are muscular chambers that pump blood into the circulatory system and into the lungs. Blood passes from the atria into the ventricles through two processes. During the "resting phase," when the ventricles are not contracting, the tricuspid and mitral valves open and allow some of the blood that has accumulated in the atria to flow passively through the valves into the ventricles. Then, the atria contract and actively pump blood out through the valves and into the ventricles. Once the ventricles fill with blood, they contract, pumping blood to the lungs and the rest of the body.
When the left ventricle cannot adequately pump blood out of the left atrium, or when one or more of the heart valves becomes leaky or narrowed (stenotic), blood can "back up" into the lungs, causing "left-sided" heart failure. When this occurs, the lungs become congested with fluid (called pulmonary edema), causing difficulty breathing and interfering with the movement of oxygen from the lungs into the bloodstream, causing fatigue. When an abnormality or condition affects the flow of blood through the right ventricle, pressure in the blood vessels increases and fluid is forced from the blood vessels into body tissues. This "right-sided" heart failure causes swelling (edema), usually in the feet and legs, and sometimes, in the abdomen.