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Published Date: 30-Nov-2008

 

Congenital Heart Disease

Picture of a physician listening to a newborn

One in 125 babies born in the United States has a heart defect present at birth (also known as Congenital Heart Disease). This is a problem that occurred as the baby's heart was developing during pregnancy. Congenital heart defects are the most commonly occurring birth defect.

A baby's heart begins to develop at conception and is completely formed by eight weeks into the pregnancy. Congenital heart defects happen during this crucial time of the baby's development. Specific steps must take place in order for the heart to form correctly. Often, congenital heart defects are a result of one of these steps not happening at the right time, leaving a hole where a dividing wall should have formed, or a single blood vessel where two ought to be, for example.

What causes congenital heart disease?

The vast majority of congenital heart defects have no known cause. Mothers will often wonder if something they did during the pregnancy caused the heart problem. In most cases, nothing can be attributed to the heart defect. Some heart problems do occur more often in families, suggesting there may be a genetic link. Some heart problems are likely to occur if the mother had a disease while pregnant and was taking medications, such as anti-seizure medicines. However, most of the time, there is no identifiable reason as to why the heart defect occurred.

Congenital heart problems range from simple to complex. Some heart problems can be watched by the baby's physician and managed with medicines, while others will require surgery, sometimes as soon as in the first few hours after birth. A baby may even "grow out" of some of the simpler heart problems since these defects may simply close up on their own with growth. Other babies will have a combination of defects and require several operations throughout their lives.

What are the different types of congenital heart defects?

Congenital heart defects can be classified into several categories in order to better understand the problems the baby will experience. They include:

  • problems that cause too much blood to pass through the lungs
    These defects allow oxygen-rich (red) blood that should be traveling to the body to re-circulate through the lungs, causing increased pressure and stress in the lungs.

  • problems that cause too little blood to pass through the lungs
    These defects allow blood that has not been to the lungs to pick up oxygen (and, therefore, is oxygen-poor or blue ) to travel to the body. The body receives less oxygen with these heart problems, and the baby will be cyanotic, or have a blue coloring.

  • problems that cause too little blood to travel to the body
    These defects are a result of underdeveloped chambers of the heart or blockages in blood vessels that prevent the proper amount of blood from traveling to the body to meet its needs.

Iin some cases there will be a combination of several heart defects, making for a more complex problem that can fall into several of these categories.

Problems that cause too much blood to pass through the lungs include the following:

  • patent ductus arteriosus (PDA) - this defect allows blood to mix between the pulmonary artery and the aorta. Prior to birth, there is a passageway (ductus arteriosus)  between the two blood vessels, which closes soon after birth. When it does not close, it is referred to as a "patent", or open. A PDA allows extra blood to flow to the lungs. PDA is often seen in premature infants.

Anatomy of a heart with a patent ductus arteriosus

  • atrial septal defect (ASD) - in this condition, there is an abnormal opening between the two upper chambers of the heart - the right and left atria - allowing mixing in either of the two chambers. Some children may have no symptoms and appear healthy. However, if the ASD is large, permitting a large amount of blood to pass through the right side of the heart, enlargement of the heart will occur and symptoms can sometimes be noted.

Anatomy of a heart with an atrial septal defect

  • ventricular septal defect (VSD) - in this condition, a hole in the ventricular septum (a dividing wall between the two lower chambers of the heart - the right and left ventricles) occurs. Because of this opening, blood from the left ventricle flows back into the right ventricle. This causes an extra volume of blood to be pumped into the lungs by the right ventricle, which can create congestion in the lungs described as "pulmonary overcirculation". Too much blood flow to the lungs can cause fast breathing, poor weight gain and enlargemnet of the heart.

Anatomy of a heart with ventricular septal defect

  • atrioventricular canal (AVC or AV canal) - atrioventricular canal is a complex heart problem that involves several abnormalities of structures inside the heart, including atrial septal defect, ventricular septal defect, and improperly formed mitral and/or tricuspid valves. The defect results in pulmonary overcirculation and often leaky valves.

Anatomy of a heart with an atrioventricular canal defect

Problems that cause too little blood to pass through the lungs include the following:

  • tricuspid atresia - in this condition, there is no tricuspid valve, therefore, no blood flows from the right atrium to the right ventricle. Tricuspid atresia defect is characterized by the following:

    • a small right ventricle

    • a large left ventricle

    • either diminished pulmonary circulation or pulmonary overcirculation

    • cyanosis - bluish color of the skin and mucous membranes caused from a lack of oxygen.

    A surgical shunting procedure is often necessary to increase the blood flow to the lungs.

Anatomy of a heart with tricuspid atresia

  • pulmonary atresia - a complicated congenital defect in which there is abnormal development of the pulmonary valve. Normally, the pulmonary valve is found between the right ventricle and the pulmonary artery. It has three leaflets that function like a one-way door, allowing blood to flow forward into the pulmonary artery, but not backward into the right ventricle.With pulmonary atresia, problems with valve development prevent the leaflets from opening, therefore, blood cannot flow forward from the right ventricle to the lungs.

  • transposition of the great arteries (TGA)  - with this congenital heart defect, the positions of the pulmonary artery and the aorta are reversed, thus:

    • the aorta originates from the right ventricle, so most of the blood returning to the heart from the body is pumped back out without first going to the lungs.

    • the pulmonary artery originates from the left ventricle, so that most of the blood returning from the lungs goes back to the lungs again

Anatomy of a heart with transposition of the great arteries

  • tetralogy of Fallot (TOF)  - this condition is characterized by the following four defects:

    1. ventricular septal defect, that allows blood to pass from the right ventricle to the left ventricle without going through the lungs

    2. a narrowing (stenosis) at or just beneath the pulmonary valve that partially blocks the flow of blood from the right side of the heart to the lungs

    3. the right ventricle is more muscular than normal and often enlarged

    4. the aorta lies directly over the ventricular septal defect

    Tetralogy of Fallot results in cyanosis (bluish color of the skin and mucous membranes due to lack of oxygen).

Anatomy of a heart with tetralogy of Fallot

  • double outlet right ventricle (DORV) - a congenital heart defect in which both the aorta and the pulmonary artery are connected to the right ventricle.

  • truncus arteriosus - the aorta and pulmonary artery begin development as a single blood vessel, which eventually divides and becomes two separate arteries. Truncus arteriosus occurs when the single blood vessel fails to divide completely, leaving a connection between the aorta and pulmonary artery.

Anatomy of a heart with truncus arteriosus

Some of the problems that cause too little blood to travel to the body include the following:

  • coarctation of the aorta (CoA) - The aorta is the main artery carrying red blood from the heart to the body. In coarctation of the aorta, the aorta is narrowed or constricted, obstructing blood flow to the lower part of the body and increasing blood pressure to the upper body. Usually there are no symptoms at birth, but they can develop as 1 to 3 days after birth. If severe symptoms of high blood pressure and congestive heart failure develop, and surgery may be considered.

Anatomy of a heart with a coarctation of the aorta

  • aortic stenosis (AS) - in this condition, the aortic valve between the left ventricle and the aorta did not form properly and is narrowed, making it difficult for the heart to pump blood to the body. A normal valve has three leaflets or cusps, but a stenotic valve may have only one cusp (unicuspid) or two cusps (bicuspid).Although aortic stenosis may not cause symptoms, it may worsen over time, and surgery may be needed to correct the blockage. Sometimes  - or the valve may need to be replaced with an artificial one.

Illustration of aortic stenosis

  • hypoplastic left heart syndrome (HLHS) - a combination of several abnormalities of the heart and the great blood vessels. In hypoplastic left heart syndrome, most of the structures on the left side of the heart (including the left ventricle, mitral valve, aorta, and aortic valve) are small and underdeveloped. The degree of underdevelopment differs from child to child. The functional ability of the left ventricle can be reduced to the extent of not being able to pump an adequate blood volume to the body. Hypoplastic left heart syndrome is fatal without treatment.

 

Anatomy of a heart with hypoplastic left heart syndrome

Who treats congenital heart defects?

Babies with congenital heart problems are followed by specialists called pediatric cardiologists. These physicians diagnose heart defects and help manage the health of children before and after surgical repair of the heart problem. Specialists who correct heart problems in the operating room are known as pediatric cardiovascular or cardiothoracic surgeons.

Adult congenital heart disease is emerging as a new subspecialty within cardiology because the number of adults with congenital heart disease (CHD) is now greater than the number of babies born with CHD, as a result of the advances in diagnostic procedures and treatment interventions that have been made since 1945.

In order to achieve and maintain the highest possible level of wellness, it is imperative that those individuals born with CHD who have reached adulthood transition to the appropriate type of cardiac care. The type of care required is based on the type of CHD a person has. Those persons with simple CHD can generally be cared for by a community adult cardiologist. Those with more complex types of CHD will need to be cared for at a center that specializes in adult CHD.

For adults with CHD, guidance is necessary for planning key life issues such as college, career, employment, insurance, activity, lifestyle, inheritance, family planning, pregnancy, chronic care, disability, and end of life. Knowledge about specific congenital heart conditions and expectations for long-term outcomes and potential complications, and risks must be reviewed as part of the successful transition from pediatric care to adult care. Parents should help pass on the responsibility for this knowledge and accountability for ongoing care to their young adult children to help ensure the transition to adult specialty care and optimize the health status of the young adult with CHD.

 


Online Medical Reviewer: Bowers, Nancy A. RN, BSN, MPH
Online Medical Reviewer: Akin, Louise RN BSN
Online Medical Reviewer: Bowers, Nancy A. RN, BSN, MPH
Online Medical Reviewer: Akin, Louise RN BSN
Online Medical Reviewer: Bowers, Nancy A. RN, BSN, MPH
Online Medical Reviewer: Akin, Louise RN BSN
Online Medical Reviewer: Bowers, Nancy A. RN, BSN, MPH
Online Medical Reviewer: Akin, Louise RN BSN
Online Medical Reviewer: Bowers, Nancy A. RN, BSN, MPH
Last Review Date: 08/14/2009
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