Heart Valve Diseases
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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. Normal valves have three flaps (leaflets), except the mitral valve, which has two flaps (leaflets). 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
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 again, 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.
Heart valve disorders can arise from two main types of malfunctions:
The valve(s) does not close completely, causing some of the blood to leak backward through the valve. The heart is forced to pump more blood on the next beat, making it work harder.
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). 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.
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:
- chest pain
- palpitations caused by irregular heartbeats
- migraine headaches
- 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.
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
- syphilis (now a rare sexually transmitted disease in North American due to effective treatment) - a disease characterized by progressive symptoms if not treated. Symptoms may include small, painless sores that disappear, followed by a skin rash, enlarged lymph nodes, headache, aching bones, appetite loss, 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 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.|
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 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.|
|This condition is characterized by a pulmonary valve that does not open sufficiently, causing the right ventricle to pump harder and enlarge.|
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. 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 the monitor as an ultrasound transducer is passed over the heart.
- chest x-ray - a diagnostic test which 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) through a large artery in the leg or arm 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.
A person with heart valve disease often will need to take antibiotics before undergoing dental or other surgical procedures that cause bleeding. 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 in the heart on the vulnerable, diseased heart valve. The antibiotics help prevent against a potentially fatal infection called endocarditis, an infection of the heart's lining.
In addition, inform your dentist and other physicians if you are taking any anticoagulant medication (to prevent blood clots), because this medication can cause excessive bleeding during surgery.
Always inform your dentist and other physician(s) if you have 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 by a cardiac surgeon, 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:
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:
- Beta-blockers, digoxin, and calcium channel blockers 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 which relax the blood vessels, decreasing the force against which the heart must pump) ease the work of the heart.
Cardiac surgery may be necessary to repair or replace the malfunctioning valve(s). Cardiac surgery may include:
- Heart valve repair: In some cases, cardiac surgery on the malfunctioning valve can help alleviate symptoms. Examples of heart valve repair surgery done by our cardiac surgeons include cutting scarred flaps so they open more easily; 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 mechanism.
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 the balloon is inflated to stretch the valve open. The balloon is then removed. This procedure is sometimes used to treat pulmonary stenosis and, in some cases, aortic stenosis. There are also some special cases where a new valve can be inserted through the groin into the heart and opened up with a balloon like a stent. This is called total aortic valve replacement.
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