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Descriptions of Congenital Heart Defects

You've probably run across an abbreviation for a Congenital Heart Defect that you were unfamiliar with. This list is an attempt to gather in one place as many of the recognized CHDs as we can, with their abbreviations and a laymans explanation of what they are. This list was created by searching the internet for sites about CHDs and then simplifying and combining all the information into one page. This list was NOT created by a doctor, and is for informational purposes only.

Click on the name of the defect to go to the description.

Aortic Stenosis Atrial Septal Defect Atrioventricular Canal Defect Bicuspid Aortic Valve Coarctation of the Aorta Complete Congenital Heart Block Congenitally Corrected Transposition of the Great Arteries or Great Vessels Coronary Artery Anomaly DCRV: Double Chamber Right Ventricle Dextrocardia DiGeorge syndrome Double Aortic Arch Double Outlet Right Ventricle Ebstein's Anomaly Eisenmenger's syndrome Endocardial Fibroelastosis Holt-Oram syndrome Hypertrophic Cardiomyopathy Hypoplastic Left Heart syndrome Hypoplastic Right Heart syndrome Interupted Aortic Arch Isolated Non-Compaction of Left Ventricular Myocardium

Kawasaki Disease Left Ventricular Outflow Tract Obstruction Long QT syndrome Major Aorta/Pulmonary Collateral Arteries Marfan syndrome Mitral Valve Prolapse Noonan syndrome Partially Anomalous Pulmonary Venous Return Patent Ductus Arterious Pulmonary Atresia Pulmonary Stenosis Right Ventricular Outflow Tract Obstruction Single Ventricle Tetralogy of Fallot Total Anomalous Pulmonary Venous Drainage or Total Anomalous Pulmonary Venous Return Transposition of the Great Arteries or Vessels Tricuspid Atresia Truncus Arteriosis Ventricular Septal Defect Williams syndrome Other syndromes that involve the Heart

For more information, you might also want to try checking out the Healthopedia site: http://www.healthopedia.com/heart-diseases.html

Aortic Stenosis
Aortic stenosis is a narrowing of the aortic valve or a narrowing of the aorta directly above (supravalvar) or below (subaortic) the aortic valve. Normally, oxygen-rich blood is pumped from the left ventricle, through the aortic valve, into the aorta and then out to the body. With aortic stenosis, it makes it very hard for the heart to pump blood to the body. Depending on the severity of the stenosis, open heart surgery may be needed to correct the defect. Another option may be a balloon valvuloplasty.

Subaortic stenosis refers to a narrowing of the left ventricle just below the aortic valve, which blood passes through to go into the aorta. This stenosis limits the flow of blood out of the left ventricle. This condition may be congenital or may be due to a particular form of cardiomyopathy known as "idiopathic hypertrophic subaortic stenosis" (IHSS).

Supravalvular aortic stenosis (SVAS) is a congenital narrowing of the ascending aorta which can occur as a congenital defect itself or as one component of Williams syndrome.

Congenital aortic stenosis occurs in 3 to 6 percent of all children with congenital heart defects. Relatively few children are symptomatic in infancy, but the incidence of problems increases sharply in adulthood. Congenital aortic stenosis occurs four times more often in boys than in girls.

Atrial Septal Defect (ASD)
The septum is the wall that separates the right and left sides of the heart. A hole in the wall between the two upper chambers is called an atrial septal defect, or ASD. This is one of the least complex forms of congenital heart defect, and was one of the first types to be repaired surgically. Normally, low-oxygen blood entering the right side of the heart stays on the right side, and oxygen-rich blood stays on the left side of the heart, where it is then pumped to the body. When a defect or "hole" is present between the atria (or upper chambers), some oxygen-rich blood leaks back to the right side of the heart. It then goes back to the lungs even though it is already rich in oxygen. Because of this, there is a significant increase in the blood that goes to the lungs.

There are three different kinds of ASDs. The most common form of ASD is the secundum defect which usually occurs as an isolated defect. The primum ASD is associated with a cleft in the mitral valve which may also causing the valve to leak. The third kind of ASD is the sinus venosus defect, located in the superior portion of the atrial septum and typically associated with abnormal drainage of the right upper pulmonary vein.

Atrial septal defects can vary greatly in size. Some ASDs will close on their own and no surgery is needed. For a chart showing probability of spontaneous closure, see: Virtual Hospital: Surgery: Atrial Septal Defect . Some ASDs are closed in the catheterization lab and do not require open-heart surgery. Certain devices such as the Amplatzer Occluder, the CardioSEAL, Helex, and Clamshell Device are currently being used or have been used in the past. Some ASDs will need to be corrected with open heart surgery to restore normal blood circulation and/or to repair subsequent damage which has occurred in the heart. Many ASDs are not detected until adulthood. Left untreated for decades, potential problems include lung disease, exercise intolerance, heart rhythm abnormalities, shortened life expectancy and the increased risk of a stroke.

Atrial septal defects occur in 5 to 10 percent of all children born with congenital heart disease. For unknown reasons, girls have atrial septal defects twice as often as boys.

Atrioventricular Septal Defect (also known as atrioventricular canal defect, or AV canal)
This complex defect is best described as a large hole in the middle of the heart. It results from a lack of separation of the atria and the ventricles into separate chambers, and a lack of separation of the mitral and tricuspid valves into two separate valves. This results in a large connection between the two atria, between the two ventricles, and a single atrioventricular (or AV) valve where there should be separate mitral and tricuspid valves. In the most complex form of this defect, not only are there holes between the atria, the ventricles, and the mitral/tricuspid valves, one of the ventricles may not be properly formed, the valves may be 'over-riding' or 'straddling', or there may be an obstruction to the aorta. Because of the large amount of extra blood going to the lungs (through the septal defects), high blood pressure may occur and over time this can damage the blood vessels. In addition, the valve between the upper (atrial) and lower (ventricular) chambers might not close properly. Blood then leaks backward from the ventricular chambers to the atrial chambers. This leak is referred to as regurgitation or insufficiency of the valve. When the valve leaks, the heart has to pump more blood. This can lead to enlargement of the heart.

This defect is usually corrected in infancy with open heart surgery to restore normal blood circulation through the heart. Surgical repair consists of separation of the common AV valve into two valves, along with closure of the VSD and ASD. Some children, however, may have too complex a defect to correct in infancy, and would initially require a pulmonary artery banding. This will decrease blood flow and reduce the high pressure in the lungs. When the child is older, the band will be removed and the defect corrected with open heart surgery.

Atrioventricular canal occurs in two out of every 10,000 live births, and equally in boys and girls.

Bicuspid aortic valve
The normal aortic valve has three flaps (cusps) that open and close. A bicuspid valve has only two cusps. There may be no symptoms in childhood, but by adulthood (often middle age or older), the valve can become narrowed, making it harder for blood to pass through it, or it may start allowing blood to leak backward through it. Treatment depends on how well the valve works.

Bicuspid aortic valve is the most common congenital cardiac anomaly occurring in 1-2% of the population with males affected 4 times more frequently than females.

DCRV: Double (or Dual) Chamber Right Ventricle DCRV is a rare defect (0.5 - 2% CHD patients have this one) where there is, basically, extra muscle in the right ventricle that causes it to function as 2 ventricles. It almost always presents with a VSD. See www.emedicine.com/ped/topic612.htm for more information.

Complete heart block (complete AV block)
In this defect, the heart's electrical signal doesn't pass from the heart's own natural pacemaker in the atrium to the lower chambers. When this occurs, an independent pacemaker in the lower chambers takes over. The ventricles can contract and pump blood, but at a slower rate than the atrial pacemaker. Complete heart block is most often caused in adults by heart disease or as a side effect of drug toxicity. Heart block also can be present at birth. This is called congenital heart block. It also may result from an injury to the electrical conduction system during heart surgery. When the pacemaker in the ventricles isn't fast enough or reliable enough, an artificial pacemaker is put in. Heart block can be of varying degrees:

• First-degree heart block, or first-degree AV block, is when the electrical impulse moves through the AV node more slowly than normal. The time it takes for the impulse to get from the atria to the ventricles should be less than about 0.2 seconds. If it takes longer than this, it's called first-degree heart block. Heart rate and rhythm are normal, and there may be nothing wrong with the heart. Certain heart medicines such as digitalis can slow conduction of the impulse from the atria to the ventricles and cause first-degree AV block.
• In second-degree heart block, some signals from the atria don't reach the ventricles. This causes "dropped beats."
• In third-degree or complete heart block, no signal passes from the atria to the ventricles. This requires a pacemaker.

Congenitally Corrected Transposition of the Great Arteries (CCTGA)
In this congenital heart defect the ventricles are switched so that the left ventricle pumps blood to the lungs, and the right ventricle pumps blood out the aorta. In this defect, the position of the two ventricles is reversed so that the right atrium enters the left ventricle, and the left atrium enters the right ventricle. With this arrangement blood is flowing through the wrong ventricles, but it is still going in the correct direction, hence the term "congenitally corrected transposition". This defect is commonly associated with ventricular septal defect, pulmonic stenosis, heart block and an Ebstein-like malformation of the tricuspid valve. The normal right ventricle pumps blood to the lungs at a low pressure (about 25 mmHg). The left ventricle, pumping blood to the body, pumps at whatever pressure your blood pressure is (about 120 mmHg). With time, since the right ventricle is not built to pump to such a high pressure as the left ventricle, it may weaken, dilate, and cause symptoms.

This is an uncommon defect occurring in less than 1% of all people with congenital heart defects. Many people with this defect may live into adulthood before the defect is diagnosed and before symptoms occur.

Coarctation of the Aorta
The aorta is the main artery that sends oxygen-rich blood from the heart to the body. Coarctation of the aorta is a constricted segment of the aorta that obstructs blood flow to the body. The left ventricle has to pump harder because the pressure is high. Because of this, the heart may enlarge. Coarctations most often occur as isolated defects, but may occur with a ventricular septal defect, subaortic stenosis, or complex congenital heart defects. Surgery may be needed to correct the defect, depending on the severity of the coarctation and the presence of other congenital defects. Another option may be a balloon angioplasty.

Coarctation of the aorta occurs in about 6 to 8 percent of all children with congenital heart disease. Boys have the defect twice as often as girls do.

Coronary Artery Abnormality
Left coronary artery attached to the right side of his heart along with the right coronary artery. For more information see This site at the University of Washington.

Dextrocardia
Dextrocardia litterally means "heart on the right". If the developing heart tube bends to the left instead of the right, then the heart is displaced to the right and develops in a mirror image of its normal state. It is interesting to note that identical twins are sometimes "mirror images" of each other, one having organs in the normal positions and one having them on the opposite side of the body. This is a condition called situs inversus.

Having dextrocardia does not mean the heart is defective, it just means that it is on the right instead of the left side of the body. Assuming there are no associated vascular abnormalities, then the heart functions normally.

In cases where the heart is the only organ which is transposed, known as isolated dextrocardia, there are usually other severe cardiac abnormalities. Dextrocardia can complicate heart defect treatments in that it can make surgery even more difficult, and heart transplants for patients with dextrocardia are more difficult since the anatomy of the donor and recipient don't match.

DiGeorge syndrome
DiGeorge syndrome is a complex birth defect. In most cases there is a chromosomal defect on chromosome 22. DiGeorge consists of a particular group of symptoms frequently occurring together, including the following:

• hypoparathyroidism (underactive parathyroid gland), which results in hypocalcemia (low blood calcium levels)
• hypoplastic (underdeveloped) thymus or absent thymus, which results in problems in the immune system
• conotruncal heart defects (i.e., tetralogy of Fallot, interrupted aortic arch, ventricular septal defects, vascular rings)
• cleft lip and/or palate

• 69 percent have palatal abnormalities (such as cleft lip and/or palate)
• 30 percent have feeding difficulties
• 80 percent have conotruncal heart defects (i.e., tetralogy of Fallot, interrupted aortic arch, ventricular septal defects, vascular rings)
• 40 percent have hearing loss or abnormal ear exams
• 30 percent have genitourinary anomalies (absent or malformed kidney)
• 60 percent have hypocalcemia (low blood calcium levels)
• 40 percent have microcephaly (small head)
• 40 percent have mental retardation (usually borderline to mild)
• IQs are generally in the 70 to 90 range
• 33 percent of adults have psychiatric disorders (i.e., schizophrenia, bipolar disorder)
• 2 percent have severe immunologic dysfunction (an immune system which does not work properly due to abnormal T-cells, causing frequent infections)

Double Aortic Arch
The ascending aorta splits into 2 "arches" which pass to the right and left of the trachea and esophagus. The two arches rejoin behind the esophagus to form the descending aorta. There are two types:
Type 1 has both arches open and functioning and this type is the most common.
Type 2 has both arches intact but one is very narrow, usually the left.

Double Outlet Right Ventricle (DORV)
Normally, a ventricle has just ONE outlet. For the left ventricle, this is the aorta. For the right ventricle it is the pulmonary artery. In DORV, both of these "outlet" blood vessels - aorta and pulmonary artery -arise from the RIGHT VENTRICLE, either totally or to a great extent. Most cases of DORV have a VSD. DORV is classified based on the relationship between the VSD and the blood vessels. If the VSD is right under the aorta, it is called DORV with Sub-Aortic VSD. If it lies under the pulmonary artery, it becomes DORV with Sub-Pulmonary VSD - also called the TAUSSIG-BING anomaly. If the VSD is under both the arteries, it is called DORV with Doubly Committed VSD. Sometimes, the VSD is farther away from the arteries, and is known as DORV with Non-Committed VSD. When in addition to this, there is narrowing of the pulmonary valve (Pulmonary Stenosis), the condition is similar to Tetralogy of Fallot (ToF). If the VSD is below the pulmonary valve, the features are just like those of Transposition of Great Arteries (TGA). When the VSD is doubly committed or non committed, clinical features are variable.

Ebstein's anomaly
This defect is a downward displacement of the tricuspid valve (located between the heart's upper and lower chambers on the right side) into the heart's right bottom chamber (or right ventricle). It's usually associated with an atrial septal defect. While there is free flow of blood forward across the tricuspid valve to the right ventricle, the deformed tricuspid valve allows a large amount of blood to flow backwards from the right ventricle to right atrium when the right ventricle contracts. About 10% of cases are associated with chronic maternal lithium use. The treatment of this disorder depends on whether or not the person with it has any symptoms. Surgery is sometimes required early in life. On the other hand, people may have a normal life expectancy. Irregular and fast heartbeats (arrhythmia) frequently accompany this condition.

See the following links for more information:
HeartPoint: Ebstein's Anomaly
Congenital Heart Disease: Ebstein's Anomaly
Pediatric Cardiology: Ebstein's anomaly
Ebstein's Anomaly Very nice explanation and GREAT diagram
Children's Heart Institute | Heart Defects: Ebsstein's Anomaly
Ebstein's Anomaly, Cincinnati Childrens Hospital
Congenital Ebsteins
Congenital Heart Disease
Ebstein's Anomaly

Endocardial Fibroelastosis (EF)
Endocardial Fibroelastosis is a rare heart disorder that affects infants and children. It is characterized by an abnormal thickening of heart tissue, especially around the valves, causing abnormal enlargement of the heart (cardiac hypertrophy), especially affecting the left ventricle. Impaired heart and lung function can eventually lead to congestive heart failure. It can cause valve failure and sudden death. Endocardial Fibroelastosis may occur for no apparent reason (sporadic) or may be inherited as an X-linked or autosomal recessive genetic trait.

Eisenmenger's syndrome
Eisenmenger's complex is a ventricular septal defect combined with pulmonary high blood pressure, the passage of blood from the right side of the heart to the left (right to left shunt) and an enlarged right ventricle. It may also include a malpositioned aorta that receives blood from both the right and left ventricles (an overriding aorta). Without early surgical correction of the underlying defect, such changes may cause progressive damage small blood vessels in lung tissue (pulmonary vascular disease).

Holt-Oram syndrome
Disorder characterized by distinctive malformations of the bones of the thumbs and forearms (upper limbs) and/or abnormalities of the heart.

Hypertrophic Cardiomyopathy (HCM, HOCM, IHSS)
The main feature of Hypertrophic Cardiomyopathy is an excessive thickening of the heart muscle. Heart muscle may thicken in normal individuals as a result of high blood pressure or prolonged athletic training. In Hypertrophic Cardiomyopathy (HCM), however, the muscle thickening occurs without an obvious cause. The condition has been known by a number of other names including "hypertrophic obstructive cardiomyopathy" (HOCM), "idiopathic hypertrophic sub-aortic stenosis" (IHSS) and "muscular sub-aortic stenosis" The general term "hypertrophic cardiomyopathy" is now the most widely used and recommended. Cardiomyopathy differs from many of the other disorders of the heart in several ways, including the following:

• Cardiomyopathy can, and often does, occur in the young.
• The condition is fairly uncommon, affecting only about 50,000 Americans (adults and children).
• Cardiomyopathy is a leading cause for heart transplantation.
• The condition tends to be progressive and sometimes worsens fairly quickly.
• It may be associated with diseases involving other organs, as well as the heart.

Hypoplastic Left Heart syndrome (HLHS)
Hypoplastic left heart syndrome, or HLHS for short, means that the left side of the heart did not develop normally. Therefore, the mitral and aortic valves are usually tiny or absent, as are the the left ventricle and the first part of the aorta. Perhaps the most critical defect in HLHS is the small, underdeveloped left ventricle. In a normal heart, this chamber is very strong and muscular so it can pump blood to the body. When the chamber is small and poorly developed, it will not function effectively and cannot provide enough bloodflow to meet the body's needs. For this reason, an infant with HLHS will not live long without surgical intervention. Parents are given a number of options depending on when the diagnosis is made potentially including -- abortion of the fetus, compassionate care (no surgical intervention which results in the baby passing away usually within the first two weeks of life) or one of a number of surgical option.

There are two, possibly three, surgical options; one is cardiac transplantation, in which the heart is replaced by a donated heart,; another is a 3-staged surgical procedure and the last surgical option is only available for a subset of HLHS patients and is called a biventricular repair.

The three-step procedure is called "the Norwood" because the first operation is called the Norwood Procedure. The Norwood is done very soon after birth, usually within the first few days of life. The second step is called the hemi-Fontan (which is frequently a bi-directional Glenn operation). It sends half of the blood returning from the body to the lungs, reducing the workload on the heart. This second step is part of the preparation to transform the HLHS heart into a two-chamber pumping heart which will only function to pump blood to the body (after the third operation, all of the blood will travel passively to the lungs). The third operation is called the Fontan operation. In this operation, the other half of the blood returning from the body to the heart is sent instead to the lungs. In what used to be a uniformly fatal disease, consider the following statistics from the very best facilities treating HLHS:

• Survival following a Norwood operation is around 80%
• Survival following a bi-directional Glenn operation is around 100%
• Survival following a Fontan operation is around 95%
• Overall, survival at 5 years of age is around 70 - 75%

Most patients who get through the three stages do quite well. They are able to lead a fairly normal life with few restrictions. Most patients have to be on some kind of anticoagulant (like baby aspirin), many need Digoxin, some kind of diuretic (at least for some time post-operatively) and/or medications to control blood pressure. Of course they have to take antibiotics prophylactically, as do other children with severe, congenital heart defects.

The biventricular repair is only available for a small subset of HLHS infants whose left ventricle is small, but not too small. The biventricular repair is actually a series of operations which must be performed in stages, like the Norwood Procedure; however, instead of converting the heart into a two-chamber pumping heart, the bi-ventricular repair encourages growth of the small left ventricle so that ultimately the child will have a fully functional, four-chamber pumping heart. Not as many facilities have experience performing this fairly new procedure, so some research on the part of the parents may be needed to find the ideal facility for their child.

Hypoplastic left heart syndrome occurs in up to four out of every 10,000 live births. It is one of the top three heart abnormalities to cause problems in the newborn. HLHS occurs slightly more often in boys than in girls.

Hypoplastic Right Heart Disease (Pulmonary Atresia)
This defect consists of a complete obstruction of the right ventricle outflow tract due to a hypoplastic (narrowed) pulmonary artery. When the ventricular septum is intact the PDA and / or bronchial collateral arteries provide the only source of pulmonary blood flow. There are two types of this defect: A small right ventricle with a thick wall and a small but working tricuspid valve. This is the most common. The other type is to have a normal right ventricle with a complete but malfunctioning tricuspid valve.
See this Link for more information

Interupted Aortic Arch (IAA)
In this defect, part of the aorta is absent and this leads to severe obstruction to blood flow to the lower part of the body. In the immediate newborn period blood flows through the ductus into the descending aorta and reaches the lower part of the body. As the ductus closes after birth, blood pressure in the lower circulation becomes inadequate and severe symptoms develop. Most affected infants develop severe symptoms (difficulty breathing and impaired kidney function) in the first week of life and need urgent surgery.

Isolated Non-Compaction of Left Ventricular Myocardium (INLVM)
The left ventricle is made up of embryonic tissue that stopped developing completely in gestation and never finished "forming."

Kawasaki Disease
Kawasaki disease is the most common form of vasculitis that primarily affects children. The disease produces irritation and inflammation of many tissues of the body including the hands, feet, whites of the eyes, mouth, lips, and throat. High fever and swelling of the lymph nodes in the neck also are characteristic of this illness. The inflammation is uncomfortable, but resolves with time. However, the main threat from Kawasaki disease comes from its effect on the heart and blood vessels. Heart-related complications can be temporary or may affect the child long-term. The heart, particularly the coronary arteries, is affected in as many as 20 percent of children with Kawasaki disease. Another name for Kawasaki disease is mucocutaneous lymph node syndrome.

Kawasaki disease is fairly common in the US. According to the American Heart Association, the illness is a major cause of heart disease in children. About 1,800 new cases are diagnosed in the US each year, and the incidence is on the rise. Kawasaki disease has replaced acute rheumatic fever as the leading cause of acquired heart disease in children in the US and Japan.

Kawasaki disease occurs more often in Japan than in any other country. In the US, children of Asian or Asian-American heritage are affected more often than other races, although Kawasaki disease can occur in any racial or ethnic group. The vast majority of children who develop Kawasaki disease are under age 5. The average age child seen with the illness is 2 years old. It occurs in boys twice as often as in girls.

Left Ventricular Outflow Tract Obstruction (LVOTO)
This defect consists of having both atrio-ventricular and ventriculo-arterial connections. Note that neither hypertrophic cardiomyopathy nor interrupted aortic arch are considered here.
Left ventricular outflow tract obstruction (LVOTO) can occur at several levels:

• Supravalvar LVOTO seldom occurs in isolation: it is usually part of Williams syndrome.
• Valvar LVOTO in the adult patient with congenital heart disease is usually due to bicuspid aortic valve. Bicuspid aortic valve is the most common congenital cardiac anomaly occurring in 1-2% of the population with males affected 4 times more frequently than females. It usually occurs in isolation but is associated with other abnormalities in 20% of the cases, the most common being coarctation of the aorta and PDA.
• Subvalvar LVOTO is usually a ridge partially or completely encircling the left ventricular outflow tract or a long narrowing beneath the base of the aortic valve. Occasionally, there is a tunnel-like narrowing of the whole left ventricular outflow tract with a small aortic root. This type of defect affects males twice as often as females. Family members may be affected. Rarely, abnormal insertion of the mitral valve or accessory mitral leaflet may cause significant obstruction.

LONG QT syndrome (LQTS)
Long QT syndrome (LQTS) is an abnormality of the heart's electrical system. The mechanical function of the heart is entirely normal. The electrical problem is due to defects in heart muscle cell structures called ion channels. These electrical defects predispose affected persons to a very fast heart rhythm (arrhythmia) called torsade de pointes which leads to sudden loss of consciousness (syncope) and may cause sudden cardiac death.

Marfan syndrome
Children with Marfan syndrome are at risk for serious problems involving the cardiovascular system, including the following:

• mitral valve prolapse - an abnormality of the valve between the left atrium and left ventricle of the heart that causes backward flow of blood from the left ventricle into the left atrium.
• arrhythmia (or disrhythmia) - a fast, slow, or irregular heartbeat.
• aortic regurgitation - backwards leakage of blood from the aorta, through a weakened aortic valve, and into the left ventricle, resulting in stress in the left heart and inadequate blood flow to the body.
• aortic dissection - weakening of the layers inside the aorta, which can result in tears in the aortic wall and leakage of blood into the chest or abdomen; a medical emergency.

• deformities of the breastbone
• scoliosis - a sideways curvature and rotation of the vertebrae, giving the appearance that the person is leaning to one side.
• misalignment of certain bones
• joint contractures
• unusual arm span
• long fingers and toes
• dislocation of the lens in the eye

See Marfan Association UK for more information.

Major Aorta/Pulmonary Collateral Arteries (MAPCA)
Direct connections (natural shunts) from the aortic system (red blood) to the lungs.

Mitral Valve Proplaspe (MVP)
Located in the heart between the left atrium (upper chamber) and left ventricle (lower chamber), the mitral valve consists of two flaps or leaflets, which normally open and shut in coordinated fashion to allow blood to flow only in one direction -- from the atrium to the ventricle. In patients with MVP, one or both of the flaps are enlarged, and the leaflets' supporting muscles are too long. Instead of closing evenly, one or both of the flaps collapse or bulge into the atrium, sometimes allowing blood to flow backwards into the atrium. The condition produces a distinctive "clicking" sound that can be heard when listening to the heart with a stethoscope.

This defect is very common in its mild form, and requires minimal medical attention. In the severe form, it usually leads to heart failure and requires surgical repair or replacement of the mitral valve. Occasionally, MVP leads to a condition known as mitral regurgitation or insufficiency. This means a large amount of blood is leaking backward through the defective valve instead of continuing in the normal direction. Mitral regurgitation can result in the thickening or enlargement of the heart wall, caused by the extra pumping the heart must do to compensate for the backflow of blood. Mitral regurgitation sometimes causes fatigue or shortness of breath. The condition can usually be treated with medication, but a few people require surgery to repair or replace the defective valve.

Although MVP affects 5% to 7% of the population, the cause is unknown. Mitral valve prolapse occurs more often in women than men; it often occurs in people who have no other heart problems, and the condition may be inherited.

Noonan syndrome
Noonan syndrome is a genetic condition that affects the heart, growth, blood clotting, and mental and physical development. The children affected may have no obvious signs to the onlooker, but the problems may be many and complex with no clinical test available. Affected individuals may have behavior problems, learning difficulties and many other anomalies, including a distinctive facial appearance; a broad or webbed neck; a low hairline in the back of the head; and short stature. Characteristic abnormalities of the head and facial area may include widely set eyes; vertical skin folds that may cover the eyes' inner corners; drooping of the upper eyelids; a small jaw; a low nasal bridge; and low-set, prominent, abnormally rotated ears.

Distinctive skeletal malformations are also typically present, such as abnormalities of the breastbone (sternum), curvature of the spine (kyphosis and/or scoliosis), and outward deviation of the elbows. Many infants with Noonan syndrome also have heart defects, such as obstruction of proper blood flow from the lower right chamber of the heart to the lungs (pulmonary valvular stenosis). Additional abnormalities may include malformations of certain blood and lymph vessels, blood clotting and platelet deficiencies, mild mental retardation, and/or other symptoms.

In some affected individuals, Noonan syndrome appears to result from spontaneous genetic mutations. In others, the disorder may be transmitted as an autosomal dominant trait. Genetic analysis suggests that the disorder may result from mutations of a gene located on the long arm (q) of chromosome 12 (12q24).

Partially Anomalous Pulmonary Venous Return (PAPVR)
This defect is associated with ASD and is also associated with hypogenetic lung (scimitar syndrome). The defect is almost exclusively right-sided. In almost all instances, the anomalous vein is a pulmonary vein. It usually drains into the infradiaphragmatic IVC. Less commonly drainage is to hepatic, portal or azygous veins, the coronary sinus or right atrium. Occasionally, the PAPVR drains to the left atrium ("meandering pulmonary vein"). In many cases of scimitar syndrome, part of the right lung receives arterial blood supply from the descending thoracic aorta or upper abdominal aorta.

Patent Ductus Arteriosus (PDA)
A PDA, or patent ductus arteriosus, is a connection (called the ductus arteriosus) between the aorta and the pulmonary artery that doesn't close off after the baby is born. In utero, the baby depends on the ductus to get oxygen from the mother, since the lungs are not working (the baby doesn't breathe in utero). When the baby is born, there are hormonal changes in the baby that normally close off the ductus, since the baby is now breathing and no longer needs it. If the ductus remains open, it may cause an excessive amount of blood to go to the lungs. Depending on the size of the PDA and the condition on the lungs, the baby may have no symptoms, or be in severe heart failure. Patent ductus arteriosus is often closed in the cardiac catheterization laboratory by the insertion of specially designed coils. These coils sit in the PDA and expand to the point where they block all the blood flow.

Patent ductus arteriosus is the sixth most common congenital heart defect, occurring in 5 to10 percent of all children with congenital heart disease. Patent ductus arteriosus occurs twice as often in girls as in boys.

Pulmonary atresia (PA)
No pulmonary valve exists, so blood can't flow from the right ventricle into the pulmonary artery and on to the lungs. The right ventricle acts as a blind pouch that may stay small and not well developed. The tricuspid valve is often poorly developed, too. An opening in the atrial septum lets blood exit the right atrium, so venous (bluish) blood mixes with the oxygen-rich (red) blood in the left atrium. The left ventricle pumps this mixture of blood into the aorta and out to the body. The only source of lung blood flow is the patent ductus arteriosus (PDA), an open passageway between the pulmonary artery and the aorta. If the PDA narrows or closes, the lung blood flow is reduced to critically low levels. This can cause very severe cyanosis. Early treatment often includes using a drug to keep the PDA from closing. A surgeon can create a shunt between the aorta and the pulmonary artery to help increase blood flow to the lungs. A more complete repair depends on the size of the pulmonary artery and right ventricle. If they are very small, it may not be possible to correct the defect with surgery. In cases where the pulmonary artery and right ventricle are a more normal size, open-heart surgery may produce a good improvement in how the heart works. If the right ventricle stays too small to be a good pumping chamber, the surgeon can compensate by connecting the right atrium directly to the pulmonary artery. The atrial defect also can be closed to relieve the cyanosis.

Pulmonary atresia occurs in about one out of every 10,000 live births.

Pulmonary Stenosis (PS)
Pulmonary stenosis is a narrowing of the pulmonary valve. Normally the pulmonary valve opens to let low-oxygen blood flow from the right ventricle to the lungs where the blood is oxygenated. Because of the narrowing, the right ventricle has to pump harder to get past the stenotic valve. This can sometimes lead to enlargement of the right ventricle. With pulmonary stenosis, problems with the pulmonary valve make it harder for the leaflets to open and permit blood to flow forward from the right ventricle to the lungs. In children, these problems can include:

• a valve that only has one or two leaflets instead of three.
• a valve that has leaflets that are partially fused together.
• a valve that has thick leaflets that do not open all the way.

Pulmonary stenosis is the second most common congenital heart defect, comprising 5 to 10 percent of all cases. It is a component of half of all complex congenital heart defects.

Right Ventricular Outflow Tract Obstruction (RVOTO)
Right ventricular outflow tract obstruction (RVOTO) can occur at any level. Supravalvar RVOTO seldom occurs alone. It may occur as part of Tetralogy of Fallot, Williams syndrome, Noonan syndrome or in combination with an ASD.
Valvar RVOTO, the most common form of RVOTO, is caused by stenosis of the pulmonic valve. It is almost always congenital in origin.
Subvalvar RVOTO usually occurs in combination with other defects, particularly VSD and Tetralogy of Fallot.
RVOTO (either valvar or subvalvar) may occur in association with subaortic stenosis.

Single Ventricle (SV)
While the normal heart has two ventricles, in some birth defects, one of these ventricles may be absent or poorly developed. This condition is called single ventricle or univentricular heart. This can include such problems as tricuspid valve atresia, hypoplastic left-heart syndrome, hypoplastic right-heart syndrome (pulmonary atresia with intact ventricular septum), mitral valve atresia, and double-inlet ventricle. Other types of heart defects, such as atrioventricular canal defects or double outlet right ventricle, may be complicated by an underdeveloped ventricle. The ventricular structure may resemble the normal left ventricle or the normal right ventricle. Sometimes it resembles neither, and this is called indeterminate ventricle morphology. Single-ventricle defects are among the most complex congenital heart problems known

In a single ventricle heart, there are two normal atria. These open into the ventricle through an atrio-ventricular (AV) valve. There might be two AV valves, both opening into the ventricle - a condition called Double Inlet Ventricle, or there may be one AV valve only, the other one being absent (atretic). The single ventricle connects with the aorta and pulmonary artery. These two great arteries may be normal or interchanged in position. Some patients have obstruction of the great arteries - pulmonary stenosis and sub-aortic stenosis.

The main problem with a single ventricle is the mixing of blood inside the ventricular chamber. Unoxygenated blood from the veins enters the right atrium and from there reaches the single ventricle. Oxygenated blood returning from the lungs flows into the left atrium and into the single ventricle. Inside the ventricle, both mix together. From here, the mixed blood flows into the aorta and pulmonary artery.

Patients with single-ventricle defects often need multiple operations. These include shunts such as Blalock-Taussig (B-T) or Glenn, placing a band on the pulmonary artery, or the Fontan operation. The Fontan operation largely separates the heart into two circulations. This lets oxygen-poor blood go to the lungs and oxygen-rich blood go to the body. The Fontan operation substantially reduces the mixing of blue and red blood and produces a normal or near-normal oxygen supply to the body. It also reduces the risk of a stroke or other complications, and decreases the workload on the single ventricle. A Fontan operation can't be done if you have pulmonary hypertension (high blood pressure in the lungs).

Tetralogy of Fallot (TOF)
Tetralogy of Fallot is one of the most common forms of complex congenital heart defects that causes cyanosis, or a blue baby. Tetralogy of Fallot is comprised of four separate components.

• The first one is a ventricular septal defect (VSD).
• The second one is pulmonary stenosis (PS).
• The third component is right ventricular hypertrophy, which is an increase in the size of the right ventricle.
• The final component is an overriding aorta, which means that the aorta lies directly over the ventricular septal defect.

Tetralogy of Fallot occurs in about two out of every 10,000 live births. Tetralogy of Fallot occurs equally in boys and in girls.

For more information, check out these sites:
http://www.kumc.edu/kumcpeds/cardiology/tetralogydfct.html
http://www.childrenheartinstitute.org/educate/defects/tetra2.htm

Transposition of the Great Arteries (or Vessels) (TGA/TGV)
In this congenital heart defect, the aorta (the main artery that carries blood to the body) originates from the right ventricle and the pulmonary artery (the artery that carries low-oxygen blood to the lungs) from the left ventricle. Because of this reversal, the aorta carries low-oxygen blood from the right ventricle to the body. The pulmonary artery carries oxygen-rich blood back to the lungs. In order for the infant born with transposition of the great arteries to survive, they must have some communication between the right and the left sides of the heart to allow-oxygen-rich blood to reach the body. This mixing of blood is possible through an ASD, VSD or PDA. Even though there is mixing of oxygenated and de-oxygenated blood, it is often not adequate to sustain life for an extended period of time. Babies with transposition are extremely blue at birth. The most common surgical procedure to correct this defect is called an arterial switch operation. That is, the major arteries are "switched". The aorta is connected to the left ventricle and the pulmonary artery is connected to the right ventricle. The ASD, VSD and/or PDA may also be needed to be corrected to restore normal blood flow.

TGA occurs in 5 to 7 percent of all congenital heart defects. Sixty to 70 percent of the infants born with the defect are boys.

Total anomalous pulmonary venous drainage (TAPVR)
Pulmonary veins normally bring oxygenated blood back from the lungs to the left atrium. In TAPVR all the pulmonary veins drain into the right atrium. In order for the infant to survive, they must have some communication between the right and left sides of the heart to allow-oxygenated blood to reach the body. This is always an ASD, although a VSD may be present as well. Because this oxygenated blood is so dilute, the infant may appear blue or "cyanotic".

There are three main types of TAPVR, depending on where the pulmonary veins drain. There are referred to as supracardiac, intracardiac, and infracardiac. There may also be a mixed type, in which two or more types may coexist. Open heart surgery is needed in early infancy. The surgery involves removal of the pulmonary veins from the right atrium and attaching them left atrium. The ASD is also closed, along with any abnormal connections that may be present.

TAPVR occurs in one out of every 15,000 live births. It occurs in boys just as often as in girls.

Truncus Arteriosus
In this defect, only one artery originates from the heart and forms both the aorta and the pulmonary artery. The truncus arises above a VSD that is almost always associated with this defect. The truncus receives low-oxygen blood from the right ventricle and oxygen-rich blood from the left ventricle. This mix of high and low-oxygen blood is sent out to the body and to the lungs. Open heart surgery in infancy is needed to correct this defect. The surgery involves closure of the VSD and removal of the pulmonary arteries from the truncus. The pulmonary arteries are then connected to the right ventricle with a prosthetic tube. This prosthetic tube usually needs to be replaced as the infant grows.

Truncus arteriosus occurs in less than one out of every 10,000 live births. It makes up 1 percent of all cases of congenital heart disease.

Tricuspid Atresia
In tricuspid atresia, there's no tricuspid valve so no blood can flow from the right atrium to the right ventricle. As a result, the right ventricle is small and not fully developed. Survival depends on there being an opening in the wall between the atria (atrial septal defect) and usually an opening in the wall between the two ventricles (ventricular septal defect). As a result, the venous (bluish) blood that returns to the right atrium flows through the atrial septal defect and into the left atrium. There it mixes with oxygen-rich (red) blood from the lungs. Most of this poorly oxygenated mixture goes from the left ventricle into the aorta and on to the body. The rest flows through the ventricular septal defect into the small right ventricle, through the pulmonary artery and back to the lungs. Often in these children it's necessary to do a surgical shunting procedure to increase blood flow to the lungs. Some children with tricuspid atresia have too much blood flowing to the lungs. They may need a procedure (pulmonary artery banding) to decrease blood flow to the lungs. Other children with tricuspid atresia may have a Fontan procedure. In this, a connection is created between the right atrium and pulmonary artery. The atrial defect is also closed. This eliminates the cyanosis but, without a right ventricle that works normally, the heart can't work totally as it should.

Tricuspid atresia occurs in two out of every 10,000 live births. It makes up 1 to 2 percent of all cases of congenital heart disease. TA occurs equally in boys and girls.

Ventricular Septal Defect (VSD)
A ventricular septal defect, or VSD, is the most common kind of congenital heart defect. Normally, blood entering the right side of the heart stays on the right side (this is low-oxygen blood), and blood on the left side of the heart stays on the left side (this is oxygen-rich blood) which is then pumped to the rest of the body. When a defect or "hole" is present between the ventricles (or lower chambers), blood from the left side of the heart is forced through the defect to the right side every time the heart beats. It then goes back to the lungs even though it is already rich in oxygen. Because of this, blood that is not yet oxygen-rich can't get to the lungs. The most common signs and symptoms are trouble eating and gaining weight, breathlessness and easy fatigability. A baby with a large VSD tires quickly after not eating very much, falls asleep, wakes us in a short while quite hungry, tries to eat again, tires easily, and the cycle is repeated. Because the heart has to pump extra blood, it may enlarge. Also, because there's more blood going to the lungs, high pressure may occur in the blood vessels there. This may cause permanent damage to the walls of the blood vessels over time. Many, if not most, of all VSDs will close on their own. Those that close on their own are usually small and do so in the first year of life. Large VSDs, especially those that don't close in the first year of life, will usually need to be closed surgically. VSD closure is one of the most commonly performed congenital heart operations. The child would be expected to have virtually normal growth, development, and life expectancy following repair.

Williams syndrome
Williams syndrome is a very complex birth defect that can have some or all of the following defects.

• Characteristic facial appearance
• Heart and blood vessel problems
• Hypercalcemia (elevated blood calcium levels)
• Low birth-weight / low weight gain
• Feeding problems
• Irritability (colic during infancy)
• Dental abnormalities
• Kidney abnormalities
• Hernias
• Hyperacusis (sensitive hearing)
• Musculoskeletal problems
• Overly friendly (excessively social) personality
• Developmental delay
• learning disabilities
• attention deficit

Here is a list of links to sites with information on other syndromes that may include heart problems:

• Allagile syndrome
• Apert syndrome
• Carpenter syndrome
• Cayler syndrome , aka Asymmetric Crying Facies with Cardiac Defects.
• CHARGE syndrome
• De Lange syndrome
• Ehler-Danlos syndrome
• Ellis Van Crevald syndrome
• Emery-Dreifuss Dystrophy
• Fanconi Anemia
• Friedreich ataxia
• Heterotaxy syndrome
• Holt-Oram syndrome
• The CaF Directory - IVEMARK SYNDROME
• Kartagener syndrome
• Laurence-Moon-Biedle syndrome
• Leopard syndrome
• Mucopolysaccharidosis
• Muscular dystrophy (Duchenne type)
• Osler-Weber-Rendu syndrome aka Hereditary Hemorrhagic Telangiectasia or HHT
• Progeria aka Hutchinson-Gilford syndrome
• Rubella syndrome
• Scimitar syndrome
• Shprintzen syndrome aka Velocardiofacial syndrome or VCFS
• Shones Syndrome
• Smith-Lemli-Opitiz syndrome
• Smith Magenis Syndrome
• TAR syndrome aka Thrombocytopenia and absent radius
• Treacher Collins syndrome
• Tuberous Sclerosis
• VACTERL syndrome
• VATER syndrome
• Von Hippel Lindau syndrome
• Wolff-Parkinson-White Syndrome (found with Ebsteins's Anomaly)
  see also: Congenital Heart Disease
• Zellweger syndrome