Congenital Heart Disease
Congenital heart diseases are defects in the heart and major blood vessels that are present at birth and occur at various stages of fetal development. About one out of every 120 live-born babies is born with a congenital heart defect.
Signs of a congenital heart disorder include:
- Heart murmurs (abnormal beating of the heart) of different types, depending on location and the nature of the disorder
- Symptoms of heart failure, including increased breathing rate, difficulty breathing, a rapid heartbeat
- "Blue baby" syndrome, in which the skin turns bluish or purplish from lack of oxygen
- Clubfoot or the enlargement of the fingers and toes with an overhanging nail
- An abnormal increase of circulating red blood cells
- Enlargement of the liver
- A pulse that is hard to hear or no pulse
- Cold hands and feet
- Signs of organ failure, including low urine output or kidney failure
- Enlargement of the chambers of the heart resulting from the need to work harder to overcome the defect
Causes and Risk Factors
Some congenital heart disorders are caused by genes. Some defects traced to abnormal chromosomes may cause severe heart defects while others result in less severe problems.
Others may result from an illness of the mother, such as diabetes (insulin production problems) or rubella (a form of measles), exposure to certain drugs or alcohol, fetal alcohol syndrome or combinations of all of these.
If an unborn child has an immediate relative (a sibling or parent) who had a congenital heart disease, he or she has a two to three percent risk of being born with a congenital heart disease. The risk increases if the relative was a parent.
Diagnosis of a congenital heart defect is based on finding that the heart is not working properly as indicated by the symptoms above. After taking a medical history, a physician will perform a physical examination, an electrocardiogram (measures electrical action of the heart) and a chest X-ray. These are usually enough to find a defect.
Other tests may be done, such as:
- Echocardiography (ultrasound to check how well the heart is operating)
- Cardiac catheterization (inserting a tube into the heart)
- Angiocardiography (injecting a special substance to allow viewing of the heart and blood vessels)
- Other laboratory studies may be needed to confirm that there is a congenital heart disorder and how severe it is
If a baby is born with bluish or purplish skin from lack of oxygen, a thorough search for causes other than congenital heart defects will be made as well. This condition is often a result of respiratory problems, including blockages in the air passages of the lung, the presence of large masses where the lung should be or a disease that prevents oxygen getting to the blood. Additional causes may include an abnormally low body temperature, low blood sugar, disorders of the central nervous system, a lack of calcium in the blood or an infection.
Specific congenital heart defects:
- Aortic valve stenosis. This is when the opening of the valve (movable part that allows blood to flow) of the aorta is narrowed because of problems with the valve. This type of defect makes up about five percent of all diagnosed heart defects. Because this defect is often not discovered, it may likely be the most common heart defect.
- Atrial septal defect, which is about six to 10 percent of congenital heart disease. This is a hole in the wall that separates two arteries.
- Coarctation of the aorta, which is a narrowing of the interior space of the aorta in a localized area. This accounts for seven to eight percent of congenital heart defects.
- Complete or partial artrioventricular canal defect. In this defect, there is a hole in the wall that separates either the atrial chambers of the heart or the ventricles at the level of the valves. It makes up about five percent of congenital heart disease. It usually is accompanied by abnormalities in the mitral or tricuspid valve.
- Patent ductus arteriosus. In a developing fetus, a duct connects the pulmonary (lung) artery with the aorta. It takes blood directly from the right chamber of the heart to the aorta, bypassing the lungs. This is possible because the fetus is receiving oxygen from its mother's blood circulation. About the time a baby is born, this duct closes because the baby will breathe using its own lungs at birth. If the duct doesn't close, this defect occurs. As many as 80% of infants who are born two or more months early have this condition.
- Persistent truncus arteriosis. This is a defect in which a single vessel does not divide to form the aorta and the artery that leads to the lungs in a developing fetus. As a result, the arteries that go to the lungs branch off from the aorta instead of coming from the right ventricle of the heart.
- Pulmonic valve stenosis. This is an abnormality of the pulmonary (lung) valve, which limits the size of the opening of the valve. Pulmonic stenosis (narrowing) of varying degrees constitutes about 10 percent of congenital heart disease.
- Tetralogy of Fallot, a defect in which there is a blockage out of the right chamber and defect in the wall between the chambers.
- Transposition of the great arteries. This is a defect where the aorta comes directly from the right ventricle and the artery to the lungs comes from the left ventricle. This is the opposite of a normal heart. As a result, the body doesn't get enough oxygen. This condition accounts for five to seven percent of all congenital heart defects.
- Underdeveloped left ventricle syndrome
- Ventricular septal defect, in which there are one or more openings in the wall separating the ventricles of the heart. They may close up on their own in infancy or they may require surgery to close. They may also lead to heart failure or be accompanied by disease in the blood vessels of the lungs.