Heart Information Center


For the heart to function properly, the four heart chambers must beat in an organized manner. Under normal conditions, the heart valves let blood to flow in only one direction. Problems with a heart valve (or valves) may occur because of disease, injury or congenital factors. Two kinds of problems usually occur. If a valve is narrowed (stenotic) the heart may have to work much harder to pump blood across the valve. A second type of problem occurs when a valve (or valves) does not close completely, causing some blood to be pumped backwards (regurgitation / incompetence) instead of forwards in the heart. Both types of problems can cause the heart to work too hard and eventually weaken over time.

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What are heart valves?

Heart valves are thin flexible flaps of connective tissue. The four heart valves are:

  1. the tricuspid valve, located between the right atrium and right ventricle;
  2. the pulmonary or pulmonic valve, between the right ventricle and the pulmonary artery;
  3. the mitral valve, between the left atrium and left ventricle; and
  4. the aortic valve, between the left ventricle and the aorta.

Blood flow occurs only when there's a difference in pressure across the valves that causes them to open.

Each valve has a set of flaps (also called leaflets or cusps). The mitral valve has two leaflets while the other valves have three. The mitral and tricuspid valves are connected to small muscles (papillary) along the wall of the heart by small string like tendons (chordeae tendineae). Papillary muscle contraction opens these valves. The aortic and pulmonic valves are differently shaped do not have cordae tendineae nor papillary muscles.

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Heart valve disorders

Valvular problems may be caused by infection, heart disease, trauma or congenital valvular conditions and may be isolated to a single valve or effect multiple valves. Right sided (tricuspid, pulmonary) valvular disease is much less common than left sided (aortic, mitral) valvular disease. Roughly 90% of valvular disease is chronic, having developed gradually over many years. Complications of rheumatic fever, congenital disorders and aging cause the vast majority of chronic valvular disease. The remaining 10% of valvular disease that develops acutely (over days to weeks) is often due to complications of recent heart attack or infections.

Infection

Rheumatic fever- Most valvular heart disease is still caused by childhood rheumatic fever (a complication of untreated streptococcal infection). During a streptococcal infection (typically in the throat) the body makes its' own antibodies to fight the bacterial infection. Antibodies recognize the structure of certain parts of the bacterial surface, attach to it and destroy it. Unfortunately, the surface structure of certain body tissues (heart valves, skin, joints, kidneys, etc..) may resemble that on certain types of streptococcal bacteria. With rheumatic fever antibodies that normally fight infection may attack the body's own tissues. It is important to stress that it is not bacteria that directly cause injury.

Rheumatic fever usually occurs 2-6 weeks after untreated strep throat. Symptoms of rheumatic fever are multiple and may include:

  • Fever
  • Arthritis (pain, swelling and warmth) that shifts from joint to joint. Larger joints such as hips and knees tend to be more frequently effected.
  • Heart failure, new heart murmurs, fast heart rate or pericardial friction rub due to inflammation of heart muscle, valves or pericardium. This is called carditis and occurs during rheumatic fever. Carditis is different from delayed valvular disease that slowly develops over many years after rheumatic fever has occurred. The latter is due to slow but progressive thickening of effected heart valves initially injured during rheumatic fever..
  • Nodules may form under the skin on the backs side of the wrist, elbow, and knees
  • a temporary skin rash lasting several days may occur.
  • Injury to brain tissues may cause repetitive involuntary writhing movement of the head and arms. This is called chorea.

The incidence of rheumatic fever in the USA has decreased greatly in recent years due to the use of antibiotics to treat strep throat. Delayed symptoms of heart valve disease may take 10-20 years to appear and gradually worsen over time. Rheumatic fever may effect a single or multiple valves. Symptoms that occur years later is usually from injury to the mitral and aortic valves.

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Infective Endocarditis is infection of heart valves directly with bacteria or fungi. Infection may occur after certain dental /surgical procedures or with IV drug use. Infective endocarditis can involve any heart valve but most commonly involves the aortic or mitral valve (left sided heart disease). Infection of only the tricuspid valve (right sided disease) is usually seen in IV drug users.

During dental or surgical procedures a small amount of bacteria may get into the blood stream. This is almost never a problem for otherwise healthy persons with normal heart valves- the body easily takes care of this on its own. Bacteria from these procedures can infect previously injured heart valves (usually from rheumatic fever). Therefore, a dose of an antibiotic (prophylactic=preventative) is always recommended prior to dental work and certain types of surgery for people with heart valve disorders to prevent endocarditis.

Vegetations (a mixture of bacteria and blood clots) may form on valves of the left, right or both sides of the heart. Vegetations can embolize (break loose) and travel to other parts of the body. Emboli from the left heart valves (mitral or aortic) will travel via the aorta to the body; those from the right heart valves (tricuspid or pulmonic) will travel to the lungs. Emboli lodging in the brain can cause a stroke. Emboli may carry infection to other parts of the body. Emboli lodging in the lungs may cause shortness of breath and cough.

Endocarditis is divided into several categories

Acute endocarditis usually occurs on previously normal valves and is most often due to IV drug use and is due to aggressive types of bacteria associated with contaminated needles. Rapid destruction of the heart valve(s) can happen, causing severe heart failure.

Symptoms of acute infective endocarditis may include:

  • fever and chills
  • weakness
  • fast heart rate
  • shortness of breath and chest pain.

People are usually quite ill. Heart murmurs may be heard as well. Stroke symptoms may occur if vegetations break loose and lodge in brain arteries. Severe heart failure may occur if the aortic or mitral valves rupture.

Subacute endocarditis usually occurs on artificial or previously injured valves and progresses more slowly. Bacteria associated with subacte endocarditis are not as virulent as bacteria associated with acute endocarditis. Symptoms of subacute infective endocarditis,often not as obvious, may include:

  • recurrent fever
  • weight loss
  • decreased appetite
  • feeling very run down

People often think they have recurrent flu or may have been treated with antibiotics several times with antibiotics for presumed bacterial infections such as bronchitis.

As in the case of acute infective endocarditis bacterial vegetations can break loose and go to other parts of the body. Physical signs are related to the part of the body they lodge in:

  • small hemorrhages may be seen in finger and toe nail beds;
  • retinal hemorrhages may be seen in the eyes;
  • tender nodules (Osler nodes) may be felt on finger and toe tips;
  • nontender plaques (Janeway lesions) may occur on the palms of the hands and soles of the feet.

Diagnosis of infective endocarditis is made if blood cultures are positive for bacteria or fungi known to cause endocarditis and there is evidence of valvular injury or vegetations. The heart and valves are imaged using echocardiography.

Treatment generally requires hospitalization and intravenous antibiotic therapy for at least 4 weeks. Infection is almost never adequately treated with oral antibiotics. Persons with severe valvular destruction may require valve replacement.

Prevention is extremely important because infective endocarditis is so difficult to treat and can cause severe disability or death. All persons with evidence of valvular injury or deformity should take preventative antibiotics before dental or surgical procedures are performed. If you have a known heart murmur or valvular problem consult your dentist and doctor prior to dental or surgical procedures.

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Heart disease

Papillary muscle dysfunction ( papillary muscles do not work properly) may occur from a heart attack, cardiomyopathy or congestive heart failure. This can cause regurgitation to occur across the tricuspid or mitral valves. Rupture of a papillary muscle (usually after a heart attack) may cause sudden regurgitation of blood back into the lungs. This may cause severe breathing problems due to excess fluid in the lungs- this is called congestive heart failure.

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Calcific aortic stenosis is a degenerative condition that is the most common cause of aortic stenosis in people over 70. Calcium deposits cause narrowing of the aortic opening. Blood flow to the aorta is partially blocked causing the left ventricle to work harder. This may eventually cause the left ventricle to weaken and not pump blood efficiently.

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Congenital valvular conditions (present at birth)

Bicuspid aortic valve ( aortic valve has 2 cusps instead of 3 cusps) is the most common cause of aortic stenosis in all people. Persons with a bicuspid valve often develop symptoms in their 50's.

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Mitral valve prolapse (click murmur syndrome)is a condition that has caused much debate and controversy in the medical community. Mitral valve prolapse (MVP) occurs when one or both of the mitral valve leaflets push back (bow) into the left atrium during contraction of the left ventricle. MVP is probably only important if a person has both excess bowing of the mitral leaflets into the atrium and actual regurgitation of blood from the left ventricle to the left atrium when the heart contracts.

The use of echocardiogram (ultrasound of the heart) over the past 20 years has revolutionized examination of the heart. Using earlier ultrasound criteria it was estimated 5-10% of the population has MVP. However, recent studies suggest that slight bowing of the mitral valve (not accompanied by regurgitation) is normal for many people and that MVP was likely over diagnosed because of the ability of ultrasound to see extremely small variations in the mitral valve shape. Using revised criteria it is believed that MVP is present in less than 1% of the general population.

People, particularly women, with heart palpitations due to anxiety often see a doctor and have heart evaluation (including ultrasound) performed. Many persons with a panic (anxiety) disorder were found to have mild mitral valve bowing on ultrasound- It was believed that panic attacks were more common in people with mitral valve prolapse. Newer studies suggest there is no correlation between panic attacks and mitral valve prolapse. Most patients who had ultrasounds and were diagnosed with MVP did not have true MVP but simply normal variation in the shape of their mitral valve. For many patients and physicians it may have been easier to accept that a physical condition was responsible for panic attacks. Most people have no symptoms of MVP.

Persons with MVP having demonstrated regurgitation are at slightly increased risk of developing endocarditis during dental/surgical procedures and should receive antibiotic prophylaxis. A very small number are at increased risk of sudden death.

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Mitral Valve Disorders

The mitral valve normally allows one way flow of blood from the left atrium to the left ventricle. Disorders of the mitral valve may cause mitral valve stenosis, mitral valve regurgitation or mitral valve prolapse (previously discussed).

Mitral Stenosis is narrowing of the mitral valve opening that usually gradually occurs over time due chronic scarring. Rheumatic fever is still the most common cause of mitral valve stenosis.

As the mitral opening narrows the left atrium enlarges (dilates) over time because it must work harder to pump blood into the left ventricle. Many people (upto 50%) eventually develop atrial fibrillation because of progressive dilatation of the left atrium. In atrial fibrillation the left atrium quivers instead of effectively pumping blood to the left ventricle causing a decreased amount of blood to the left ventricle.

Severe stenosis may also cause pressure to built up in the lung blood vessels (pulmonary veins) that supply blood to the left atrium. The lung blood vessels are normally under much lower pressure (as is the right side of the heart that pumps blood to the lungs) than the left ventricle, aorta and its' arterial branches. Increased blood pressure in the lungs is called pulmonary hypertension.

Symptoms may not appear for many years but are usually due to congestive heart failure. The first ( and most common) symptom to appear is usually shortness of breath (beyond normal) during physical activity. Any stimulus that rapidly increases heart rate or blood flow can cause sudden increase in lung congestion and cause shortness of breath. Other factors responsible for shortness of breath in those with mitral stenosis (in additional to physical activity) include stress, fever, pregnancy, or onset of atrial fibrillation. As the disease worsens shortness of breath at rest or while lying down may occur. Severe disease is common with pulmonary hypertension.

The second most common symptom to initially appear is coughing up blood due to rupture of a bronchial (lung) vein.

Blood clots are more likely to form in the left atrium during atrial fibrillation - these blood clots (emboli) may dislodge and travel to other body organs including the brain, eyes, heart and kidneys. The risk of stroke or heart attack (due to emboli traveling to the brain or coronary arteries) is higher in persons with atrial fibrillation.

Diagnosis of mitral stenosis is suspected in a person with a history of congestive heart failure, findings of a specific type of mitral heart murmur on physical exam, and suggestive chest x-ray and EKG findings. Definitive diagnosis is made using ultrasound- The entire valve can be visualized.

Cardiac catheterization ( dye is injected into a blood vessel near the heart and movie-like pictures taken) is performed if surgical repair or replacement of the mitral valve is considered. Catheterization will detect if there is narrowing of the coronary arteries. Coronary artery disease increases the risk of heart attack during surgery and may need to be corrected prior to surgical valve repair or replacement.

Treatment depends on the severity of symptoms, health and age of an individual, amount of mitral valve narrowing, and whether coexisting aortic valvular disease is present. Persons requiring treatment for this disorder must be under the care of a physician!

  • Persons without symptoms and mild to moderate stenosis do not need to restrict physical activity.
  • Persons with mild symptoms (shortness of breath) with physical activity are usually started on a mild diuretic, a low salt diet, advised to avoid vigorous exercise and extreme stress. ACE inhibitors may be used in conjunction with diuretics.
  • Blood thinning agents (coumadin) are recommended with mitral stenosis, particularly if atrial fibrillation is present, to decrease the risk of embolization to other areas of the body.
  • Persons with symptoms should be evaluated by a cardiologist. Valvular repair or replacement should not be delayed until symptoms occur at rest or with minimal exertion. This is particularly true for younger persons who are otherwise healthy.

Surgical treatment options include:

  1. Percutaneous balloon mitral valvulotomy- a balloon tipped catheter is threaded through an artery into the heart. The balloon is inflated to expand the mitral valve. This technique has been very effective in younger patients with valves that are not calcified (excessively stiff).
  2. Surgical valvulotomy (commisurotomy)- the natural valve is widened by making a cut in the mitral valve.
  3. Total valve replacement- the mitral valve is replaced by a prosthetic ("artificial")valve. Valves may be either bioprosthetic (pig, cow, or human) or synthetic (usually metal alloys). Valvular replacement is usually required in older patients with heavily calcified (stiff) mitral valves.

Prognosis

Most people have no symptoms the first 10 years, increasing shortness of breath on exertion the next 10 years followed by worsening symptoms that may begin to occur at rest during the next decade.

All people having mitral stenosis of any degree require antibiotic prophylaxis to prevent infective endocarditis prior to dental or surgical procedures.

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Mitral Regurgitation occurs when blood flows back into the left atrium from the left ventricle during left ventricular contraction because of a "leaky" mitral valve. Mitral regurgitation can occur acutely (suddenly) with infective endocarditis or with a heart attack that causes rupture of the papillary muscles or chordae tendineae. Symptoms of severe congestive heart failure ( severe shortness of breath, fast heart rate, and fluid in the lungs) requiring urgent surgical intervention usually occur with acute mitral valve rupture.

Rheumatic fever is the most common cause of chronic (gradual over many years) mitral regurgitation. Chronic regurgitation, even with large regurgitant blood flow, is often tolerated for years due to compensatory changes in the heart. The left atrium dilates over time to handle the increased blood volume.

Symptoms are very similar to mitral stenosis. As with mitral stenosis the most common first symptom is shortness of breath with exertion, atrial fibrillation is common in later stages and the risk of emboli is as high as 20%. Most emboli travel to tissues that do not cause symptoms. However, emboli traveling to the brain may cause stroke and emboli traveling to the coronary arteries may cause heart attack.

Diagnosis may be made by a person giving a history of shortness of breath with exertion and the doctor hearing a heart murmur suggestive of mitral regurgitation. As with all valvular disorders definitive diagnosis is made with ultrasonography. Persons considered for valvular repair or replacement will have cardiac catheterization performed.

Treatment is similar to that for mitral stenosis except balloon valvuloplasty is not performed unless the mitral valve is also stenotic. Most cases of mitral regurgitation do not involve significant stenosis. Valve replacement or reconstruction is indicated for most persons with severe symptoms (shortness of breath at rest or with minimal exertion.

Anticoagulation ( blood thinning agents) is recommended for those with mitral regurgitation, especially persons with atrial fibrillation, due to increased risk of stroke from emboli.

Prognosis- The time course from the presence of this disease to the first symptoms is similar to that for mitral stenosis.

All people having mitral regurgitation require antibiotic prophylaxis to prevent infective endocarditis prior to dental or surgical procedures.

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Aortic Valve Disorders

The aortic valve normally allows one way flow of blood from the left ventricle to the aorta. Disorders of the aortic valve may cause aortic valve stenosis or aortic valve regurgitation.

Aortic Stenosis is narrowing of the aortic valve.

Causes include:

  1. congenital heart disease (bicuspid valve)- most common cause
  2. rheumatic heart disease- second most common
  3. degenerative heart disease (calcific aortic stenosis)- most common in persons over 70 years of age.

What happens with aortic stenosis?

As the aortic valve narrows the left ventricle must work harder to pump the same amount of blood through a narrower opening. The left ventricle is the largest and strongest pumping chamber of the heart- it must pump blood to the entire body. The left ventricular muscle increases in size (hypertrophies) over time to compensate for the extra work it must perform. The strength and ability of the left ventricle to compensate for increased work load may mask the symptoms of aortic stenosis for many years until the valve becomes extremely narrow. When the aortic valve narrows past a certain point the left ventricle can no longer fully compensate. Not as much blood can be pumped across the aortic valve to the body, particularly during activities requiring increased blood flow to the organs and muscles. At this point symptoms may appear.

Symptoms include:

  1. Shortness of breath with exertion. This symptom may occur earlier in very physically active people. This is usually the first symptom but is not specific for aortic stenosis.
  2. Shortness of breath awakening a person from their sleep (second most common symptom).
  3. Passing out (syncope) with exertion, angina, or heart attack are also common and indicate severe disease.

Who gets aortic stenosis?

Most people do not develop symptoms until late in the course of aortic stenosis. Age at onset of symptoms (clinically apparent aortic stenosis) usually indicates the cause of aortic stenosis. Symptoms in people younger than 30 years is almost always due to congenital causes (usually bicuspid aortic valve). Symptoms in people 30-70 years may be due to either bicuspid valve or rheumatic heart disease. Aortic stenosis caused by rheumatic fever occurs 10-15 years later than mitral stenosis caused by rheumatic fever. Symptoms developing in the elderly are usually due to calcific degenerative changes of a normal aortic valve (wear and tear of aging).

How is aortic stenosis detected?

People may see their doctor concerning symptoms of aortic stenosis. Chest pain or passing out during exertion is very concerning and may prompt a doctor into examining the heart in detail. If aortic stenosis is present a certain type of heart murmur may be detected when a doctor listens with a stethoscope. The doctor may order further tests. Aortic stenosis can be definitively diagnosed using echocardiogram (heart ultrasound).

Atrial fibrillation and traveling emboli are less common in isolated aortic stenosis.

Is aortic stenosis serious?

Once symptoms develop aortic stenosis is very serious. The presence of symptoms almost always means that the aortic valve is extremely narrow and will not tolerate further narrowing. Once symptoms occur with aortic stenosis, particularly angina or shortness of breath with minimal exertion or congestive heart failure, many people die within several years if not treated.

Sudden death, due to cardiac arrhythmias, may occur in upto 20% of people with aortic stenosis. The cause of sudden death is speculative (unknown).

How is aortic stenosis treated?

  • Asymptomatic persons with mild stenosis do not have to limit physical activity.
  • Periodic monitoring should be done because rapid narrowing can occur over as little as a few years.
  • Persons with more severe stenosis should be evaluated by a cardiologist whether or not they have symptoms.
  • Persons with symptoms of passing out on exertion, angina or congestive heart failure due to aortic stenosis require immediate evaluation by a cardiologist and may be considered for valve repair or replacement.
  • Your doctor may treat symptoms of either angina or congestive heart failure with medications as they occur. If these symptoms are caused by aortic stenosis definitive treatment is valve repair or replacement. Very old age (80's) is not a contraindication to valve replacement as long heart function and overall health are reasonable.

    Persons requiring treatment for this disorder must be under the care of a physician!

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Pulmonary and Tricuspid Valve Disorders

Isolated valvular disorders of the right side of the heart (receiving and pumping venous blood to the lungs for oxygenation) are much less common than left sided valvular disease. Combined left (mitral and/or aortic) and right (tricuspid and/or pulmonic) heart valvular disease is more common.

Tricuspid Valve Disorders - Tricuspid valve normally allows one way blood flow from the right atrium to the right ventricle.

  • Isolated tricuspid disease is most commonly due to endocarditis from IV drug use.
  • Right ventricular failure causing tricuspid regurgitation is usually due to heart attack effecting the right ventricle
  • Tricuspid disease and left sided valvular disease due to rheumatic fever may occur.

Pulmonary Valve Disorders - Pulmonic valve normally allows one way blood flow from the right ventricle to the pulmonary (lung) arteries.

  • Pulmonary stenosis most frequently caused by a congenital defect (Tetralogy of Fallot) that is detected and surgically corrected in infancy.
  • Pulmonary regurgitation (incompetence) is most commonly due to pulmonary hypertension.

Symptoms

  • Shortness of breath, particularly while laying flat are the most common initial symptoms of tricuspid and pulmonary valve disorders. Symptoms of worsening disease, in addition to shortness of breath, include swelling of the feet, liver, abdomen or neck veins due to fluid retention.

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Artificial (Prosthetic) Valves

Artificial valves are placed in over 40,000 persons a year in the United States. There are more than six dozen types of valves. Prosthetic valves can be grouped into two main categories:

  1. Mechanical (nontissue models) usually made of metal or composite alloys.
  2. Tissue valves(bioprostheses) made from pig, cow or human valves.

Discussion of individual valve types is beyond the scope of this article. Readers having questions about specific valve types or technical details must consult with their doctor, cardiologist or cardiothoracic surgeon. Patients with prosthetic valves should always carry a card that describes their valve.

What type of problems occur with prosthetic valves?

Are more common in patients having more advanced heart disease (cardiomyopathy, congestive heart failure, and/or arrhythmias) at time of valve replacement.

  • Prosthetic valves may be slightly narrow (stenotic). A small amount of regurgitation, due to incomplete closing, is common.
  • Thrombi (blood clots) can form on prosthetic valves. If thrombi become large enough they can interfere with blood flow or prevent the valve from closing properly.
  • Thrombi can embolize. This is the most important complication of mechanical (nontissue) valves. This occurs in about 1% of people per year with mechanical valves. This is not as common in tissue valves. Those with mechanical valves almost always need to take blood thinning medications (anticoagulation). Not all tissue valves require anticoagulation.
  • Bioprostheses may gradually deteriorate.
  • Mechanical valves often cause anemia due to increased red blood cell destruction.
  • Rarely, mechanical valves can suddenly fail (break). This is often fatal.
  • Endocarditis is more likely to occur on artificial valves.

    What symptoms occur with prosthetic valve problems?

    Many patients have ongoing shortness of breath and decreased exercise tolerance after successful valve replacement. This is more likely in persons with poorer heart function or atrial fibrillation.

  • Persons with a sudden decrease in normal exercise tolerance or new chest pain should see their doctor.
  • In addition to these symptoms people with prosthetic valve problems may experience symptoms of emboli. Minor episodes (temporary) are common and can include stroke like symptoms, abdominal pain (emboli blocking intestinal blood vessels), and arm or leg pain (emboli blocking muscle blood vessels). Major blockages can cause stroke, heart attack, and permanent intestinal injury.
  • Severe hemorrhage can occur during anticoagulation therapy. People on anticoagulants noticing blood in the urine, feces, saliva or new skin bruising must see their doctor.
  • Those with fever should see their doctor urgently. Fever could indicate infective endocarditis.

Patients with prosthetic valves should receive antibiotic prophylaxis before dental and surgical procedures.

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Glossary

Atrial fibrillation left atrium of heart ineffectively quivers instead of normally contracting.
Arrhythmia irregular beating of the heart that may cause the heart to beat too fast or slow. Certain arrhythmias may cause the heart to stop beating.
Chorea repetitive involuntary writhing movement of the head and arms.
Congenital a condition present at birth
Congestive heart failure the heart can't pump enough blood to meet the needs of the body's other organs.
Echocardiography a technique that views the heart valves using sound waves and a computer generated image. Also called a heart ultrasound.
Heart murmur sound caused by turbulent blood flow across a heart valve(s) heard by a doctor using a stethoscope.
Heart valves are thin flexible flaps of connective tissue normally permitting one-way blood flow through the heart.
Palpitations An uncomfortable awareness of the heart beating. May be slow, normal or fast.
Pericardium a tough fibrous layer of tissue normally covering the heart.
Pericardial friction rub a sound heard with a stethoscope due to rubbing of the heart against the pericardium that may occur with inflammation of the pericardium.
Pulmonary hypertension

increased pressure in the lung veins and arteries. These vessels are normally under lower blood pressure than arteries arising from the aorta and its' branches. May contribute to or be caused by chronic congestive heart failure. Often secondary to increased left atrial pressure, due to mitral stenosis, causing blood to back up in the lungs.

Regurgitation backward flow of blood through a heart valve. Also called valvular incompetence.
Stenosis narrowing of the valve opening
Virulence the ability of an infection to cause illness / injury to the body.