Congestive heart failure facts
- Congestive heart failure (CHF) is a condition in which the heart’s function as a pump is inadequate to meet the body’s needs.
- Many disease processes can impair the pumping efficiency of the heart to cause congestive heart failure.
- The symptoms of congestive heart failure vary, but can include fatigue, diminished exercise capacity, shortness of breath, and swelling.
- The diagnosis of congestive heart failure is based on knowledge of the individual’s medical history, a careful physical examination, and selected laboratory tests.
- The treatment of congestive heart failure can include lifestyle modifications, addressing potentially reversible factors, medications, heart transplant, and mechanical therapies.
- The course of congestive heart failure in any given patient is extremely variable.
What is congestive heart failure?
Congestive heart failure (CHF) is a condition in which the heart’s function as a pump is inadequate to deliver oxygen rich blood to the body. Congestive heart failure can be caused by:
- diseases that weaken the heart muscle,
- diseases that cause stiffening of the heart muscles, or
- diseases that increase oxygen demand by the body tissue beyond the capability of the heart to deliver adequate oxygen-rich blood.
The heart has two atria (right atrium and left atrium) that make up the upper chambers of the heart, and two ventricles (left ventricle and right ventricle) that make up the lower chambers of the heart. The ventricles are muscular chambers that pump blood when the muscles contract. The contraction of the ventricle muscles is called systole.
Many diseases can impair the pumping action of the ventricles. For example, the muscles of the ventricles can be weakened by heart attacks, infections (myocarditis) or toxins (alcohol, some chemotherapy agents). The diminished pumping ability of the ventricles due to muscle weakening is called systolic dysfunction. After each ventricular contraction (systole) the ventricle muscles need to relax to allow blood from the atria to fill the ventricles. This relaxation of the ventricles is called diastole.
Diseases such as hemochromatosis (iron overload) or amyloidosis can cause stiffening of the heart muscle and impair the ventricles’ capacity to relax and fill; this is referred to as diastolic dysfunction. The most common cause of this is longstanding high blood pressure resulting in a thickened (hypertrophied) heart. Additionally, in some patients, although the pumping action and filling capacity of the heart may be normal, abnormally high oxygen demand by the body’s tissues (for example, with hyperthyroidism or anemia) may make it difficult for the heart to supply an adequate blood flow (called high output heart failure).
In some individuals one or more of these factors can be present to cause congestive heart failure. The remainder of this article will focus primarily on congestive heart failure that is due to heart muscle weakness, systolic dysfunction.
Congestive heart failure can affect many organs of the body. For example:
- The weakened heart muscles may not be able to supply enough blood to the kidneys, which then begin to lose their normal ability to excrete salt (sodium) and water. This diminished kidney function can cause the body to retain more fluid.
- The lungs may become congested with fluid (pulmonary edema) and the person’s ability to exercise is decreased.
- Fluid may likewise accumulate in the liver, thereby impairing its ability to rid the body of toxins and produce essential proteins.
- The intestines may become less efficient in absorbing nutrients and medicines.
- Fluid also may accumulate in the extremities, resulting in edema (swelling) of the ankles and feet.
Eventually, untreated, worsening congestive heart failure will affect virtually every organ in the body.
Picture of the heart and valves, left and right ventricles, left and right atria
What causes congestive heart failure?
Many disease processes can impair the pumping efficiency of the heart to cause congestive heart failure. In the United States, the most common causes of congestive heart failure are:
- coronary artery disease
- high blood pressure (hypertension)
- longstanding alcohol abuse
- disorders of the heart valves
- unknown (idiopathic) causes, such as after recovery from myocarditis
It should also be noted that in patients with underlying heart disease, taking certain medications can lead to the development or worsening of congestive heart failure. This is especially true for those drugs that can cause sodium retention or affect the power of the heart muscle. Examples of such medications are the commonly used nonsteroidal anti-inflammatory drugs (NSAIDs), which include ibuprofen (Motrin and others) and naproxen (Aleve and others) as well as certain steroids, some medication for diabetes (such as rosiglitazone [Avandia] or pioglitazone [Actos]), and some calcium channel blockers.