Congestive heart failure is present when heart failure develops over enough time for excessive fluid — the congestion — to build up. Heart failure occurs when the heart is unable, for whatever reason, to pump blood at the rate and volume necessary to meet the metabolic needs of the other body tissues, primarily the need for oxygen. The heart’s only function is to pump blood carrying oxygen and nutrients out to the body tissues, and back again carrying waste products. A healthy heart manages to do this under many varying conditions, ranging from the low metabolic needs of sleep to the high needs of running a marathon.
Heart failure is not a disease itself but is the final result of many diseases, both of the heart and of other organs. Heart attacks caused by coronary artery disease, severe valve damage caused by rheumatic fever, hypertension, even severe anemia may all lead to heart failure. Heart failure may occasionally occur abruptly, following a massive heart attack or large blood clot to the lungs, and may result in shock and rapid death. Usually though, the heart failure develops slowly, over a period of months to years, as the heart’s pumping ability deteriorates. The heart itself and other organs in the body adapt to the reduced pumping in various ways, and it may be difficult to say when the heart actually began to fail.
One of the body’s adaptations is to try to increase the volume of the blood by retaining salt and water through the kidneys. This retained fluid causes many of the symptoms of congestive heart failure. The excessive salt and fluid cause swelling of the ankles, called edema. Fluid may build up in the abdominal organs, mostly the liver, which will enlarge and cause the abdomen to bulge. In a more advanced case, free fluid may accumulate in the abdominal cavity, a condition called ascites.
Fluid also builds up in the lungs and may cause a variety of symptoms by interfering with breathing. Shortness of breath, called dyspnea, may occur only with exercise or, in an advanced case, may be present even at rest. Orthopnea is a particular type of shortness of breath that occurs when lying down flat. Someone with this symptom must sleep propped up on pillows. Chronic cough is also a common symptom.
Because the underlying cause of the congestive heart failure often progresses slowly, someone who develops symptoms abruptly may have another condition that precipitates the heart failure: heart attack, many infections, pneumonia, pregnancy, hyperthyroidism, blood transfusions, and others. If such a precipitating condition can be found and treated, the heart failure may subside.
In the past few years, new medical and surgical treatments for heart failure have been developed. Although the surgical treatment, removing part of the deteriorated left ventricle to improve overall function is still experimental, the new medical treatments which include the use of one of a class of drugs known as ACE inhibitors and a drug from the class known as beta blockers have brought about great improvements in the treatment of this condition.