Valvular heart disease refers to several disorders and diseases of the heart valves, which are the tissue flaps that regulate the flow of blood through the four chambers of the heart.
Description
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 backwards 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:
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.
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.
Infective endocarditis
Anyone who was born with a defective hart 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 may also need to receive injected antibiotics prior to procedures involving the bladder, prostate, and pelvic organs.
The use of appetite suppressants
In 1997 and early 1998, research was underway to determine if fen-phen, the abbreviation for a combination of the two weight-loss drugs fenfluramine and phentermine, 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. The drug's manufacturer removed fenfluramine from the market until further study was conducted.
Other valvular heart disease
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 can also damage the mitral valve structures. Additionally, certain connective tissue disorders can adversely affect the heart valves, for example, Marfan's syndrome and myxomatous degeneration.
Diagnosis
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.
Appetite suppressants
The drug associated with valvular heart disease, fenfluramine, was not available on the market as of mid-1998.
Treatment
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.
Prognosis
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.
Prevention
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.
BOOKS
Current Medical Diagnosis and Treatment, 1996. 35th ed. Ed. Stephen McPhee, et al. Stamford: Appleton & Lange, 1995.
Congenital—Used to describe a condition or defect present at birth.
Stenosis—An abnormal valve condition which is characterized by tightening or narrowing of the opening.
Streptococcal (Streptococcus)—Streptococcus is a bacterium that causes infection in people. Its most commonly known strain causes the infection strep throat.
Throat culture—A test for strep throat that involves swabbing the back of the throat and sending the swab to a laboratory, which will determine whether bacteria is present.
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