Congenital Heart Defects: The Basics
A congenital heart defect (CHD) is a defect of the heart that is present at birth, meaning children are born with the problem rather than acquiring it later in life. There are many kinds of CHDs ranging from those that are very minor and may go undetected for many years to others that are very serious and require immediate intervention.
Defects can occur inside the heart or in the large blood vessels outside the heart. One surgery may be enough to repair a heart defect, but sometimes a series of procedures are needed as the child grows and develops. The doctors can use different approaches depending on the severity and location of the defect. In some cases, a special tube is used to perform the surgery through an artery in the groin (cardiac catheter) resulting in a much faster recovery period. Other defects may require a closed heart surgery (thoracotomy) where the surgeon makes an incision between the ribs on the side of the body. The third option is the most invasive surgery; it is a full open-heart procedure requiring a sternotomy or incision right down the middle of the breastbone and commonly a heart-lung bypass machine. The most common types of CHDs will be discussed in detail below.
A normal heart consists of 4 chambers – 2 atria and 2 ventricles. The main pumping chamber of the heart is the left ventricle. It pumps oxygenated blood up to the aorta to go right around the whole body and to be returned by veins to the right side of the heart and lungs to pick up more oxygen before the process starts all over again. CHDs can happen in many different areas of the heart and blood vessels. This simple diagram shows the main heart structures and how they relate to each other.
Types of CHD
As mentioned, there are many different types of CHDs ranging from minor (which may not even be picked up until school) to extremely serious and complicated (usually picked up immediately or shortly after birth). In many cases, the family may know of the CHD but may not be able to afford the surgery and so the child progresses and things may worsen until H2H can step in to assist. The most common types of CHD are described briefly below.
Patent ductus arteriosus (PDA)
Before birth, a blood vessel runs between the aorta (the main artery to move oxygenated blood around the body) and the pulmonary artery (the main artery to the lungs) and is called the ductus arteriosus. Normally this small vessel closes shortly after birth when a baby starts to breathe on their own. If it does not close, it is called a patent ductus arteriosus, meaning it is still “patent” or open. This type of CHD can be often fixed using the less invasive types of procedures with a small device being passed through a catheter to block or tie off the PDA or sometimes they close themselves after a few months.
Coarctation of the Aorta
Coarctation of the aorta occurs when a part of the aorta has a very narrow section, making it difficult for blood to get through to be pumped around the body. Over time, it can lead to other problems such as extremely high blood pressure. To repair this defect a thoracotomy is often needed and the narrow part of the aorta patched, stented or replaced.
Atrial Septal Defect (ASD)
The atrial septum is the wall between the left and right atria (upper chambers) of the heart. A hole(s) in that wall is called an ASD. In the presence of this defect, blood with and without oxygen can be mixed up and over time can cause problems and abnormal heart rhythms. Sometimes, an ASD can be closed without open-heart surgery using a catheter or thoracotomy to patch up the hole. If the defect is more difficult, open-heart surgery may also be done to repair an ASD using stitches.
Ventricular Septal Defect (VSD)
The ventricular septum is the wall between the left and right ventricles (lower chambers) of the heart. A hole(s) in the ventricular septum is called a VSD. This hole lets blood with oxygen mix with used blood returning to the lungs. Over time, irregular heartbeats and other heart problems can happen if the defect is not fixed. This is performed in a similar way to the ASDs described above.
Tetralogy of Fallot (TOF)
TOF is generally a more serious type of CHD and involves a group of 4 (“tetra”) defects in the heart. These include a VSD, pulmonary stenosis (narrowing), a misplaced aorta and a thickened right ventricle. Often more than one surgery may be necessary over time starting with a shorter procedure to provide some relief before a longer operation afterwards.
Transposition of the Great Vessels (TGV)
In a normal heart, the aorta comes from the left side of the heart, and the pulmonary artery comes from the right side. In TGV, these arteries come from the opposite sides of the heart. The child may often also have other birth defects. Correcting TGV requires full open-heart surgery and is often performed shortly after birth. The most common repair is called an arterial switch where the vessels are connected to where they should be for normal heart functioning.
Other rarer conditions
There are many other rarer CHDs which may occur in isolation or in various combinations, including problems with heart valves, the heart muscle (hypertrophy) or the blood vessels in and around the heart.
CHD in China
A recent study has been the largest prevalence study ever performed about CHD in China (Qu-Ming et al; 2019). This study revealed statistics on the number of births affected by CHD in China to be similar to those in western culture at approximately 9 births per 1,000. Although there was a slight tendency towards higher numbers of females, males were affected more severely by CHD. VSDs and ASDs were the highest rate of CHDs at 3 per 1,000 and 1.7 per 1,000 respectively. The other CHDs were not as common.
CHDs can also be part of other syndromes and abnormalities, such as Downs Syndrome, in which half of the children also have a PDA, VSD, ASD or TOF as part of the syndrome when they are born.
H2H aims to help as many Chinese children as possible with CHD – regardless of the type of defect. We need your help to raise money for these surgeries. Even though we help more children each year, we will continue to need your support. Thousands of Chinese children are born to families who can’t afford the surgeries each year; we would love to help all those who need it!