Congenital heart disease (CHD) refers to heart defects that affect the structure of the heart present at birth. The severity of the disease ranges from mild defects such as a small hole in the heart, to severe and life-threatening conditions in which the heart is missing certain parts.
As a result, CHD can affect how blood flows through the heart. Depending on the type and severity of CHD, symptoms range from sleepiness or tiredness to difficulty breathing or blue-tinted nails and lips that point to insufficient oxygen supply.
In Singapore, according to the birth defect registry, from 1994 − 2000, congenital heart disease was a factor in 0.81% of total live births. Nationwide, there are about 12,000 adults living with congenital heart disease. With an average of 37,000 – 40,000 babies born each year, it is estimated that the number of adult cases will increase by 300 – 320 every year.
What are the types of congenital heart defects?
There are many types of congenital heart diseases including:
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Atrial septal defect
Atrial septal defect refers to a hole in the wall separating the two upper atriums or chambers of the heart that can damage blood vessels in the lungs. If it does not close on its own, surgery may be required. Left untreated, it can cause problems in adulthood such as high blood pressure in the lungs, abnormal heartbeat, increased risk of stroke and heart failure.
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Ventricular septal defect
Ventricular septal defect refers to a hole in the heart, a common congenital defect in the wall (septum) separating the lower chambers of the heart (ventricles). This hole redirects oxygen-rich blood to pass from the left to the right side of the heart, sending it back to the lungs instead of distributing it to the rest of the body.
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Coarctation of the aorta
Coarctation of the aorta is a condition where part of the aorta is narrower than usual, which occurs because it did not form or develop normally during pregnancy. It is a critical congenital heart defect and if the narrowing is severe, the surgery may be necessary soon after birth.
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Fallot's tetralogy or tetralogy of Fallot
Fallot's tetralogy or tetralogy of Fallot comprises of 4 defects of the heart and its blood vessels:
- a hole in the wall between the two lower chambers or ventricles (also known as a ventricular septal defect)
- narrowing of the pulmonary valve and main pulmonary artery (known as pulmonary or aortic stenosis)
- enlarged aortic valve with both ventricles opening into it
- thicker than normal muscular wall of the right ventricle (also known as ventricular hypertrophy)
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Patent ductus arteriosus
Patent ductus arteriosus (PDA) refers to an opening between the two major vessels leading from the heart. The opening is normal before birth and usually closes on its own after birth. It is only known as PDA if it remains open. A small opening may not require treatment but large openings allow poorly oxygenated blood to flow in the wrong direction. This weakens the heart muscle and can lead to complications and heart failure.
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Pulmonary atresia
Pulmonary atresia is a condition in which blood is unable to flow from the right ventricle of the heart to the lungs, because the pulmonary valve did not form at all (the pulmonary valve controls the flow of blood from the right ventricle to the main pulmonary artery). It is a critical congenital heart defect that may require surgery soon after birth.
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Pulmonary or aortic stenosis
Pulmonary or aortic stenosis is the narrowing of the pulmonary valve and main pulmonary artery. It is one of the four defects categorised under tetralogy of Fallot.
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Transposition of the great arteries
Transposition of the great arteries is a rare defect in which the two main arteries leaving the heart are reversed. This changes the way blood circulates through the body, as the blood travelling from the heart to the rest of the body is low in oxygen. It is a critical congenital heart defect.