Heart Valve Diseases

Overview

What are heart valves?

The heart consists of four chambers, two atria (upper chambers) and two ventricles (lower chambers). There is a valve through which blood passes before leaving each chamber of the heart. The valves prevent the backward flow of blood. These valves are actual flaps that are located on each end of the two ventricles (lower chambers of the heart). They act as one-way inlets of blood on one side of a ventricle and one-way outlets of blood on the other side of a ventricle. Each valve actually has three flaps, except the mitral valve, which has two flaps. The four heart valves include the following:

tricuspid valve - located between the right atrium and the right ventricle
pulmonary valve - located between the right ventricle and the pulmonary artery
mitral valve - located between the left atrium and the left ventricle
aortic valve - located between the left ventricle and the aorta

How do the heart valves function?

As the heart muscle contracts and relaxes, the valves open and shut, letting blood flow into the ventricles and atria at alternate times. The following is a step-by-step illustration of how the valves function normally in the left ventricle:

After the left ventricle contracts, the aortic valve closes and the mitral valve opens, to allow blood to flow from the left atrium into the left ventricle.
As the left atrium contracts, more blood flows into the left ventricle.
When the left ventricle contracts again, the mitral valve closes and the aortic valve opens, so blood flows into the aorta.

What is heart valve disease?

Heart valves can have one of two malfunctions:

regurgitation
The valve(s) does not close completely, causing the blood to flow backward – in addition to forward – through the valve.
stenosis
The valve(s) opening becomes narrowed or constricted, inhibiting the ability of the heart to pump blood to the body due to the increased force required to pump blood through the stiff and narrow (stenotic) valve(s).

Heart valves can have both malfunctions at the same time (regurgitation and stenosis). When heart valves fail to open and close properly, the implications for the heart can be serious, possibly hampering the heart's ability to pump blood adequately through the body.

What are the symptoms of heart valve disease?

Mild heart valve disease may not cause any symptoms. The following are the most common symptoms of heart valve disease. However, each individual may experience symptoms differently. Symptoms may vary depending on the type of heart valve disease present and may include:

shortness of breath
dizziness
fatigue
low or high blood pressure, depending on which valve disease is present
chest pain
palpitations caused by irregular heartbeats
abdominal pain due to an enlarged liver (if there is tricuspid valve malfunction)

Symptoms of heart valve disease may resemble other medical conditions and problems. Always consult your physician for a diagnosis.

What causes heart valve damage?

The causes of heart valve damage vary depending on the type of disease present and may include the following:

a history of rheumatic fever (now a rare disease in north America due to effective antibiotic treatment) - a condition characterized by painful fever, inflammation, and swelling of the joints.
damage resulting from a heart attack
damage resulting from an infection
changes in the heart valve structure due to the aging process
congenital birth defect
myxomatous degeneration - an inherited connective tissue disorder that weakens the heart valve tissue
syphilis (now a rare sexually transmitted disease in North American due to effective treatment) - a disease characterized by progressive symptoms if not treated.

The mitral and aortic valves are most often affected by heart valve disease. Some of the more common heart valve diseases include:

Heart Valve Disease	Symptoms and Causes
Bicuspid aortic valve	This congenital birth defect is characterized by an aortic valve that only has two flaps (a normal aortic valve has three flaps). If the valve becomes narrowed, it is more difficult for the blood to flow through, and often the blood leaks backward. Symptoms usually do not develop during childhood, but are often detected during the adult years.
Ebstein's anomaly	When Ebstein's anomaly is present, there is a downward displacement of the tricuspid valve (located between the upper and lower chambers on the right side of the heart) into the right bottom chamber of the heart (or right ventricle). This condition is usually associated with an atrial septal defect, an opening between the two upper chambers of the heart.
Mitral valve prolapse	This disease is characterized by the bulging of one or both of the mitral valve flaps during the contraction of the heart. One or both of the flaps may not close properly, allowing the blood to leak backward. This may result in a mitral regurgitation murmur.
Mitral valve regurgitation	This condition refers to leaking of the mitral valve when the left ventricle contracts. Some blood leaks back into the left atrium instead of moving forward into the aorta. This can occur due to diseases of the mitral valve, after a heart attack, or with diseases of the heart muscle (cardiomyopathies).
Mitral valve stenosis	Often caused by a past history of rheumatic fever, this condition is characterized by a narrowing of the mitral valve opening, increasing resistance to blood flow from the left atrium to the left ventricle.
Aortic valve stenosis	This type of valve disease mainly occurs in the elderly and is characterized by a narrowing of the aortic valve opening, increasing resistance to blood flow from the left ventricle to the aorta.
Pulmonary stenosis	This condition is characterized by a pulmonary valve that does not open sufficiently, causing the right ventricle to pump harder.

How is heart valve disease diagnosed?

Heart valve disease may be suspected if the heart sounds heard through a stethoscope are abnormal. This is usually the first step in diagnosing a heart valve disease. A characteristic heart murmur (abnormal sounds in the heart due to turbulent blood flow) can often indicate valve regurgitation. To further define the type of valve disease and extent of the valve damage, physicians may use any of the following diagnostic procedures:

electrocardiogram (ECG or EKG) - a test that records the electrical activity of the heart, shows abnormal rhythms (arrhythmias or dysrhythmias), and detects heart muscle damage.
chest x-ray - a diagnostic test which uses x-rays to produce images of internal tissues, bones, and organs onto film. An x-ray can show enlargement in any area of the heart.
cardiac catheterization - this diagnostic procedure involves a tiny, hollow tube (catheter) being inserted into an artery leading to the heart in order to image the heart and blood vessels. This procedure is helpful in determining the type and extent of valve blockage.
transthoracic and transesophageal echocardiogram (TEE) - An echocardiogram is a diagnostic test that is used to measure the sound waves that bounce off the heart, creating a graphic image of the movement of the heart structures.
magnetic resonance imaging (MRI) - a diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.

Heart valve disease and surgical procedures:

A person with heart valve disease may need to take antibiotics before undergoing dental or other surgical procedures. Antibiotics are also recommended by physicians and dentists before routine professional teeth cleaning and other procedures involving the gum or soft tissues of the mouth. Bacteria released during these and other procedures may enter the bloodstream and lodge on the diseased and vulnerable heart valve. The antibiotics help prevent a serious infection called endocarditis, an infection of the heart's lining.

Always inform your dentist and other physician(s) if you have heart valve disease.

Treatment for heart valve disease:

In some cases, the only treatment for heart valve disease may be careful medical supervision. However, other treatment options may include medication, surgery to repair the valve, or surgery to replace the valve. Specific treatment will be determined by your physician based on:

your age, overall health, and medical history
extent of the disease
the location of the valve
your signs and symptoms
your tolerance for specific medications, procedures, or therapies
expectations for the course of the disease
your opinion or preference

Treatment varies, depending on the type of heart valve disease, and may include one, or a combination of, the following:
Medication
In some cases, medication alone is successful in the treatment of heart valve disease, and may include:

Medications such as beta-blockers, digoxin, and verapamil to reduce symptoms of heart valve disease by controlling the heart rate and atrial fibrillation (arrhythmia) that can accompany heart valve disease.
Medications to control blood pressure and fluid, such as diuretics (medications that remove excess water from the body by increasing urine output) or vasodilators (medications which relax the blood vessels, decreasing the force against which the heart must pump, to reduce pressure in the lungs).

Surgery
Surgery may be necessary to repair or replace the malfunctioning valve(s). Surgery may include:

Heart valve repair: In some cases, surgery on the malfunctioning valve can help alleviate symptoms. Examples of heart valve repair surgery include cutting scarred flaps so they open more easily; remodeling valve tissue that has enlarged; or inserting prosthetic rings to help narrow a dilated valve. In many cases, heart valve repair is preferable, because a person's own tissues are used.
Heart valve replacement: When heart valves are severely malformed or destroyed, they may need to be replaced. Replacement valves fall into two categories: tissue (biologic) valves, which include animal valves and donated human aortic valves, and mechanical valves, which can be metal, plastic, or another artificial material.

Another treatment option that is less invasive than valve repair/replacement surgery is balloon valvuloplasty, a non-surgical procedure in which a special catheter (hollow tube) is threaded into a blood vessel in the groin and guided into the heart. The catheter, which contains a deflated balloon, is inserted into the narrowed heart valve and inflated, stretching the valve open. The balloon is then removed. This procedure is often used to treat pulmonary stenosis, mitral stenosis, and, in some cases, aortic stenosis.