Definition of Congestive Heart Failure

Congestive heart failure occurs when the heart muscle becomes weakened and damaged. The heart can no longer pump well enough to supply the body with enough blood and oxygen.

There are many causes of congestive heart failure, including coronary artery disease, heart attack, high blood pressure, valvular disease (the heart valves don’t close correctly), infections, drug/alcohol abuse, pregnancy and family history.

Almost 5 million Americans have congestive heart failure with more than 400,000 new cases diagnosed each year. Congestive heart failure is a major cause of hospitalization.

When the heart is unable to pump adequate amounts of blood to the body, it dilates (becomes bigger and wider). This affects specifically the left ventricle (lower chamber of the heart), which is the main pumping chamber. The heart’s dilatation (widening), is the body's attempt to compensate or correct the decrease of the pumping ability by increasing the amount of blood pushed out with each beat. However, when the heart dilates, it actually becomes a weaker muscle. Eventually, it is no longer able to pump blood.

In addition to the left ventricular enlargement, the body responds to heart damage by making hormone-like substances to try and support the failing heart. Over time, these substances actually add to the weakening of the heart. The substances increase the scar tissues within the heart and exhaust the heart by over-stimulation. This contributes to abnormal heart rhythms. Many heart failure medications are designed to combat the negative effects of these hormone-like substances.

Another result of a damaged or weakened heart muscle is the inability to pump adequate amounts of blood to the body's organs. One organ particularly affected is the kidneys. The kidneys' function is to remove water, sodium and waste products from the body. These waste products are flushed out of your body through your urine. When the blood flow is too low, the kidneys keep too much water in your body. Too much water in the body produces edema, which is the excessive accumulation of fluid in body tissue. Edema causes swelling of the feet, legs, abdomen, liver and lungs.