Congenital Heart Defects
Learning a child may have a congenital heart defect (also referred to as congenital heart disease) is scary, and figuring out where that child will receive treatment for their condition can be one of the biggest decisions a parent can make. The experts at the CHOC Heart Institute understand these anxieties and work with pediatric patients and their families to diagnose, treat and manage congenital heart disease.
What is a congenital heart defect?
A congenital heart defect, also referred to as congenital heart disease or CHD, is a heart problem that is present at birth and is caused by an error in the development of the heart during fetal development.
Types of Congenital Heart Defects
- Aortic stenosis
- Atrial septal defect
- Atrioventricular (AV) canal defect
- Coarctation of the aorta
- Heart valve problems
- Interrupted aortic arch
- Patent ductus arteriosus
- Pulmonary atresia
- Pulmonary stenosis
- Tetralogy of Fallot
- Transposition of the great arteries
- Truncus ateriosus
- Ventricular septal defect
- Single ventricle defects, including hypoplastic left heart syndrome
What causes a congenital heart defect?
In most cases, there is no known reason for the heart to form incorrectly.
Some types of congenital heart defects are known to occur more often when the mother comes in contact with certain substances during the first few weeks of pregnancy while the baby’s heart is developing. Some maternal illnesses and medications taken for these illnesses have been shown to affect the heart’s development. Other illnesses or medications seem to have no impact on the baby’s heart. Because of this, it is very important for women to speak with their doctor about the medications they take as soon as they find out they may be pregnant or when they are thinking about becoming pregnant.
Women who have seizure disorders and need to take antiseizure medications may have a higher risk for having a child with a congenital heart defect, as do women who take lithium to treat depression. Mothers who have phenylketonuria (PKU) who do not adhere to the special diet necessary to manage the disease during pregnancy have a higher risk of having a child with a congenital heart defect. Also, women with insulin-dependent diabetes (particularly if the diabetes is not well-controlled) or lupus may have a higher risk of having a child with heart defects. Counseling is very important for women with these chronic illnesses before becoming pregnant, so that they understand the risks involved.
Approximately 30 percent of children with chromosome abnormalities are born with a congenital heart defect. Some of these include:
- Down syndrome (trisomy 21)
- Trisomy 18 and trisomy 13
- Turner’s syndrome
- Cri du chat syndrome
- Wolf-Hirshhorn syndrome
- DiGeorge syndrome (22q11).
Some of the genetic syndromes associated with a higher incidence of heart defects include, but are not limited to:
- Marfan syndrome
- Smith-Lemli-Opitz syndrome
- Ellis-van Creveld
- Holt-Oram syndrome
- Noonan syndrome.
If a child has been diagnosed with a chromosomal or other genetic abnormality, genetic counseling is helpful to determine the risk for heart defects occurring in future children.
Can family history cause congenital heart defects?
In the general population, about 1 percent of all children are born with a congenital heart defect. However, the risk goes up when either parent has a CHD or when another sibling was born with a CHD.
Some heart defects are considered to have autosomal-dominant inheritance, meaning that a parent with the defect has a 50 percent chance, with each pregnancy, to have a child with the same heart defect, and males and females are equally affected. Similarly, there is also a 50 percent chance that an offspring will not be affected.
Families with a history of congenital heart defects can meet with a genetic counselor or genetic specialist before becoming pregnant to talk about the risks of passing on the defect. In families with CHD either in the parents or offspring, fetal echocardiography can be performed in the second trimester, at about 18 to 22 weeks of pregnancy, to determine the presence of major heart defects in the fetus.
How are congenital heart defects diagnosed?
Early diagnosis and treatment is very important for the ongoing management of many forms of congenital heart disease.
Many heart defects can be diagnosed prenatally. The fetal cardiology experts at the Heart Institute work with expectant families to plan for heart defects before a baby is even born.
After birth, diagnoses can be made using:
- Cardiac catheterization
- Echocardiogram
- CT scan
- Cardiac MRI
- Electrocardiogram and cardiac stress testing
- Holter monitoring
What are the different types of congenital heart defects?
Congenital heart defects are classified into several categories to better understand the problems the child will experience. They include:
- Problems that cause too much blood to pass through the lungs. These defects allow oxygen-rich blood that should be traveling to the body to recirculate 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) to travel to the body. The body does not get enough oxygen with these heart problems, and the baby may 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.
In some cases there will be a mix of several heart defects. This creates a more complex problem that can fall into several of these categories.
How are congenital heart defects treated?
Some heart problems can be watched by the baby’s doctor and managed with medicines. 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, such as patent ductus arteriosus or atrial septal defect. These defects may simply close up on their own with growth. Other babies will have a combination of defects and require several surgeries throughout their lives.
No matter the treatment needed, our cardiologists, cardiothoracic surgeons, nurses and other specialists are dedicated to providing the very best patient- and family-centered care and include the child’s family in the decision-making process every step of the way.
What chromosome abnormalities and genetic syndromes are associated with congenital heart defects?
Approximately 30 percent of children with abnormal chromosomes that result in genetic syndromes, like Down syndrome, are born with a congenital heart defect. Chromosomes are the structures in the body’s cells that contain genes. Genes code traits like eye color and blood type. Usually there are 46 chromosomes in each cell of the body. Having too many or too few chromosomes results in health problems and birth defects. Structural defects of the chromosomes, where a piece of the chromosome is missing or duplicated, also causes health problems.
There are a number of chromosome abnormalities associated with congenital heart defects. Some of these include the following:
- Down syndrome (trisomy 21)
- Trisomy 18 and trisomy 13
- Turner’s syndrome
- Cri du chat syndrome
- Wolf-Hirshhorn syndrome
- DiGeorge syndrome (22q11).
Chromosome analysis can be performed from a small blood sample to rule out the presence of a chromosome abnormality in a child with a congenital heart defect.
What are single gene defects?
There are an estimated 70,000 genes contained on the 46 chromosomes in each cell of the body. Genes come in pairs, one that is inherited from the mother, the other from the father. Genes not only compose our individual traits, but also may be responsible for health problems when gene alterations (mutations) are present. When a gene is mutated, a number of health problems may occur in a person, due to the single underlying genetic mutation. Several health problems with one genetic cause are often referred to as a syndrome. Some of the genetic syndromes associated with a higher incidence of heart defects include, but are not limited to:
- Marfan syndrome
- Smith-Lemli-Opitz syndrome
- Ellis-van Creveld
- Holt-Oram syndrome
- Noonan syndrome.
Other genetic syndromes that are not due to a single gene defect, but are associated with CHD, include Goldenhar syndrome (hemifacial microsomia), William’s syndrome and the VACTERL association (tracheal and esophageal malformations associated with vertebral, anorectal, cardiac, renal, radial and limb abnormalities).
When a child is born with a congenital heart defect, if there is a suspicion that the child has some type of genetic syndrome, a doctor who specializes in genetics (called a clinical geneticist) may be asked to evaluate the child.
If a child has been diagnosed with a chromosomal or other genetic abnormality, genetic counseling is helpful to determine the risk for heart defects occurring in future children.