The human heart consists of four chambers--two upper chambers (the atria) and two lower chambers (the ventricles) that are responsible for pumping blood. The heart valves are like one-way doors, which open and close with each beat of the heart, controlling the blood flow from one chamber to the next. Each of these valves is made up of a few thin folds of tissue. When functioning correctly, they keep blood from flowing backward into a chamber when closed.

The four valves function in the following manner:

• The mitral valve is located between the left atrium and the left ventricle. It is the only valve with two flaps, or cusps.
• The tricuspid valve is located on the right side of the heart, between the right atrium and right ventricle. It is made up of three cusps, each a different size.
• The aortic valve is located on the left side of the heart and opens to allow blood to leave the heart from the left ventricle into the aorta, which is the main artery of the body. It closes to prevent blood from flowing back into the left ventricle.
• The pulmonary valve is situated on the right side of the heart, between the right ventricle and pulmonary artery. It allows blood to exit the heart and enter the lungs via the pulmonary artery. It closes to prevent blood from flowing back into the right ventricle.

Patients with valvular heart disease have a malfunction of one or more of these valves. There are several types of valvular heart diseases with distinct symptoms and treatments. These are:

• mitral valve prolapse (displacement)
• mitral valve insufficiency (regurgitation)
• mitral valve stenosis (narrowing)
• aortic valve insufficiency
• aortic valve stenosis
• tricuspid valve insufficiency
• tricuspid valve stenosis
• pulmonic stenosis
• pulmonic insufficiency

Certain types of heart disease can lead to one of the specific conditions listed above. These include rheumatic fever and infective inflammation of the heart (endocarditis). Multivalvular heart disease refers to a condition involving more than one of the heart valves.

Problems with heart valves may occur as a result of infection, degeneration, or congenital abnormality. The most common infections are rheumatic fever and infective endocarditis.

Rheumatic fever is a condition that results from the body's immune response to certain types of streptococcal bacteria. It occurs rarely. When it occurs, it is most often in children who have had strep throat that was not completely treated. The symptoms of rheumatic fever include heart inflammation, uncontrolled movement of face and limbs, arthritis that moves from joint to joint, shortness of breath, weakness, and either lumps under the skin or raised red patches on the skin. The most common valvular heart diseases to result from rheumatic fever are mitral stenosis, tricuspid stenosis, aortic insufficiency, aortic stenosis, multivalvular involvement, and less commonly, pulmonic stenosis. Chronic rheumatic heart disease can result from one occurrence or from repeated attacks. It is not as common as it once was in the United States, but still occurs frequently in developing countries.

Infective endocarditis is an infection and inflammation of the inner layer, or membrane, of heart tissue (endocardium). Most people with a healthy, normal heart are not at significant risk for contracting infective endocarditis. However, people who have had rheumatic fever, with its resulting scarring, or a congenital cause of heart malformation, may contract this disease when certain bacteria enter the bloodstream and become lodged in the heart. In particular, dental surgery or any surgery involving the mouth, bladder, prostate, or female pelvic organs increases risk for this infection. The disease also may occur in drug addicts who inject their veins using unsterilized needles, even if they have normal heart valves. Symptoms of infective endocarditis include fever, a new or changing heart murmur, and abnormal loss of appetite or fatigue.

In 1997 the manufacturers of fen-phen, the abbreviation for a combination of the two weight-loss drugs fenfluramine and phentermine, withdrew the supplements from the market. Preliminary research showed that they caused heart valve problems in some patients. Physicians were concerned that this drug combination could affect the heart valves because the drugs alter metabolism of serotonin in the body. Serotonin is a natural substance found in the brain and intestines that can affect blood vessels. Until the issue could be studied more, physicians recommended that patients taper off the drugs, finally stopping them altogether. Eventually, the company reached a $3.75 billion settlement of most lawsuits by former users of the diet drugs.

The mitral and aortic valves may also be affected by deposits of calcium in the heart that occurs with aging. This can lead to thickening and leakage of heart valves. Heart attacks also can damage the mitral valve structures. Additionally, certain connective tissue disorders can adversely affect the heart valves, for example, Marfan's syndrome and myxomatous degeneration.

Specific types of valvular heart disease are diagnosed using electrocardiography (EKG), echocardiography, certain x-ray studies, and/or cardiac catheterization. An EKG provides a record of electrical changes in the heart muscle during the heartbeat. Echocardiography uses sound waves to make images of the heart. These images can show if there are any abnormalities of the heart valves. Cardiac catheterization is a procedure in which a small tube (called a catheter) is inserted into an artery and passed into the heart. It is used to measure pressure in the heart and the amount of blood pumped by the heart.

Rheumatic fever may be suspected when a recent throat infection has occurred and other major or minor symptoms appear, such as joint ache, abnormal EKG, or a blood test indicating heart inflammation. Heart murmurs may be detected from routine examination.

A diagnosis of infective endocarditis can be obtained through patient history, EKG, ultrasound, or cardiac catheterization. Patients who have developed the disease rapidly may report fever, fatigue, night sweats, chills, and joint inflammation. Those whose disease has developed more slowly will show signs of rapid heart rate, an enlarged spleen, various skin colors or spots, and heart murmur. The physician may order blood tests to determine what is causing the infection.

People with a history of using appetite suppressants may be sent for EKGs or further testing if any of the symptoms of valvular heart disease, such as swelling, considerable fatigue, or shortness of breath occur.

The treatment of specific valvular heart diseases will vary, depending on the valve involved and the extent of damage or malfunction. Some patients will not require treatment and many will be treated with medication. Sometimes, patients need surgery. If multivalvular disease is suspected or involved, different valves may be evaluated during surgery on one of the affected valves. Women with heart valve disease who want to become pregnant should receive a thorough check-up and see a cardiologist regularly throughout their pregnancy.

Patients with rheumatic fever will be treated with antibiotics to eliminate streptococcal organisms that may still remain in the heart. Patients may receive antibiotics to prevent further infection, and inflammation may be treated with aspirin or cortisone-like drugs.

Physicians will use the appropriate antibiotic or some combination of antibiotics to treat infective endocarditis, depending on the type of bacterium that caused the disease. Severe cases of this disease may be corrected by valve replacement surgery.

The role of appetite suppressants (fen-phen) in valvular heart disease has been under study. Many of the people who suffered complications of the diet drugs experienced regurgitation. However, some 2001 studies found that these valve problems often did not worsen or even improved after a period of time after the patients stopped taking fen-phen.

The prognosis for patients with valvular heart disease varies depending on the underlying cause, age and health of the patient, and the degree of valvular damage or involvement.

Patients with rheumatic heart disease face a lifetime of caution over contact with the same bacterium that caused the disease. Since it can cause inflammation of one or more organs or joints, complications can occur. The inflammation of the heart may subside without side effects. Permanent scarring of one or more heart valves is a possibility and may require surgery to repair or replace damaged valves. In severe cases, rheumatic fever can lead to death from heart failure.

The prognosis for patients with infective endocarditis depends on the underlying heart disease and resulting complications. If the disease further damages heart valves, symptoms may occur for years after initial treatment. Sometimes, endocarditis can result in heart or renal failure. If untreated, it can be fatal.

Since it is believed that different valves may be affected, treatment for those taking these drugs most likely follows a similar course as that for the specific valvular disease.

Certain measures can be taken to prevent some valvular disease. However, once valvular heart disease that results from congenital abnormality occurs, it may not be prevented. Steps can be taken to prevent further complications.

The best prevention for rheumatic fever is prompt and thorough treatment of any suspected streptococcal infection, particularly strep throat in children. A physician should check any sore throat with fever that persists for more than 24 hours. The physician will probably order a throat culture. Completion of the antibiotic treatment even after symptoms diminish is important to be certain the infection is eliminated.

Anyone who was born with a defective heart valve, those with artificial (prosthetic) valves, or those who have had a valve scarred by rheumatic fever, should use prescribed antibiotics by mouth before and after a dental procedure. These patients also may need to receive injected antibiotics prior to procedures involving the bladder, prostate, and pelvic organs.

The drug associated with valvular heart disease, fen-phen, was removed from the market, so as long as people avoid obtaining this appetite suppression combination, they can prevent its negative effects.