Heart Valve Diseases
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. 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. 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 close, letting blood flow into the ventricles and out to the body 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.
The left atrium contracts and more blood flows into the left ventricle.
When the left ventricle contracts, the mitral valve closes and the aortic valve opens so blood flows into the aorta and out into the systemic circulation to the rest of the body.
What is heart valve disease?
Heart valve disorders can arise from two main types of malfunctions:
Regurgitation (or leakage of the valve). The valve(s) does not close completely, causing the blood to flow backward through the valve. The heart is forced to pump more blood on the next beat, making it work harder.
Stenosis (or narrowing of the valve). The valve(s) opening becomes narrowed, limiting the flow of blood out of the ventricles or atria. The heart is forced to pump blood with increased force in order to move blood through the narrowed or stiff (stenotic) valve(s).
Heart valves can develop both malfunctions at the same time (regurgitation and stenosis). Also, more than one heart valve can be affected at the same time. 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. Heart valve problems are one cause of heart failure.
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:
Palpitations caused by irregular heartbeats
Low or high blood pressure, depending on which valve disease is present
Shortness of breath
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, a condition characterized by painful fever, inflammation, and swelling of the joints. Rheumatic fever is now rare in North America due to effective antibiotic treatment.
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
Syphilis, a disease characterized by progressive symptoms if not treated. Syphilis is a sexually-transmitted infection that is now rare in North America due to effective treatment. Symptoms may include small, painless sores that disappear, followed by a skin rash, enlarged lymph nodes, headache, aching bones, loss of appetite, fever, and fatigue.
Myxomatous degeneration, an inherited connective tissue disorder that weakens the heart valve tissue.
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 has only 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.
Mitral valve prolapse (also known as click-murmur syndrome, Barlow's syndrome, balloon mitral valve, or floppy valve syndrome)
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 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 occurs primarily 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.
This condition is characterized by a pulmonary valve that does not open sufficiently, causing the right ventricle to pump harder and enlarge.
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 across the valve) can often indicate valve regurgitation or stenosis. 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 can sometimes detect heart muscle damage.
Echocardiogram (echo). A noninvasive test that uses sound waves to evaluate the heart's chambers and valves. The echo sound waves create an image on a monitor as an ultrasound transducer is passed over the heart.
Chest X-ray. A diagnostic test that uses invisible electromagnetic energy beams 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 the insertion of a tiny, hollow tube (catheter) into an artery leading to the heart in order to provide images of the heart and blood vessels. This procedure is helpful in determining the type and extent of certain valve disorders.
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.
What is the 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. Medications are not a cure for heart valve disease, but in many cases are successful in the treatment of symptoms caused by heart valve disease. These medications may include:
Medications such as beta-blockers, digoxin, and calcium channel blockers to reduce symptoms of heart valve disease by controlling the heart rate and helping to prevent abnormal heart rhythms.
Medications to control blood pressure, such as diuretics (medications that remove excess water from the body by increasing urine output) or vasodilators (medications that relax the blood vessels, decreasing the force against which the heart must pump) to ease the work of the heart.
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 remodeling abnormal valve tissue so that the valve functions properly, 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 with an entirely new replacement valve. Replacement valve mechanisms fall into two categories: tissue (biologic) valves, which include animal valves and donated human aortic valves, and mechanical valves, which can consist of 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. Once in place, the balloon is inflated to stretch the valve open, and then removed. This procedure is often used to treat pulmonary stenosis and, in some cases, aortic stenosis.