Congenital Heart Defect

Congenital Heart Defect
A congenital heart defect is a structural problem (or defect) in the heart that is present at birth. A baby's heart begins to develop shortly after conception. During development, structural defects can occur. These defects can involve the walls of the heart, the valves of the heart, and the arteries and veins near the heart. Congenital heart defects can disrupt the normal flow of blood through the heart. The blood flow can: Slow down; Go in the wrong direction or to the wrong place; Be blocked completely; Congenital heart defect is the most common type of major birth defect. Each year, more than 30,000 babies in the United States are born with congenital heart defects.

Types of Congenital Heart Defects
There are many types of congenital heart defects. They include: Abnormal passages in the heart or between blood vessels; Problems with the heart valves; Problems with the placement or development of blood vessels near the heart; Problems with development of the heart itself.
Some of these problems are described below.

Abnormal passages in the heart or between blood vessels are Atrial septal defect (ASD) is a hole in the wall that separates the upper chambers (atria (AY-tree-uh)) of the heart. This causes blood to leak from one atrium to the other. Ventricular septal defect (VSD) is a hole in the wall that separates the lower chambers (ventricles ) of the heart. This causes blood to leak from one ventricle to the other. Atrioventricular septal defect (AVSD) includes an ASD, VSD, and abnormal development of the atrioventricular valves (tricuspid) and mitral ). This causes blood to flow abnormally inside the heart. An AVSD is also known as an atrioventricular canal defect.
Patent ductus arteriosus (PDA) is a persistent connection between the aorta and the pulmonary artery. This connection is called the ductus arteriosus and is normally present before birth. In most babies, the vessel closes within a few hours or days after birth. In some children, the vessel fails to close, resulting in PDA.

The problems with the heart valves are Congenital heart defects can involve any of the valves and include the following types of problems: Stenosis. The valve opening is narrow and does not open completely. Atresia. The valve does not form, so there is no opening for blood to pass from one chamber to another. Regurgitation. The valve does not close completely, so blood can leak back through the valve.

Examples of particular heart valve problems include: Aortic valve stenosis is a narrowing of the aortic (ay-OR-tik) valve in the heart that causes it to open incompletely. This can reduce blood flow to the body. Pulmonary valve atresia is a defect in which a solid sheet of tissue forms in place of the pulmonary valve. This prevents blood in the right side of the heart from traveling normally to the lungs to pick up oxygen. Pulmonary valve stenosis is a narrowing of the pulmonary valve. The narrowing slows the flow of blood from the right side of the heart to the lungs. The heart must pump harder to push blood through the smaller opening.
Tricuspid valve atresia is a defect in which a solid sheet of tissue forms in place of the tricuspid valve. Without the tricuspid valve, blood entering the right atrium cannot travel normally to the right ventricle and then to the lungs to pick up oxygen. Ebstein's anomaly is a defect in which the tricuspid valve is both displaced and abnormally formed. The valve leaks and allows blood to flow back into the right atrium instead of to the lungs to pick up oxygen.

Problems with placement or development of blood vessels near the heart
Transposition of the great vessels is a defect in which the location of the "great vessels" (the aorta and pulmonary artery) coming off the heart is switched. The aorta comes off the right ventricle instead of the left ventricle. The pulmonary artery comes off the left ventricle instead of the right ventricle. Therefore, blood without oxygen is continually pumped to the body, instead of blood with oxygen. Tetralogy of Fallot is a combination of four defects: Pulmonary valve stenosis is the narrowing of the pulmonary valve. The narrowing slows the flow of blood from the right ventricle to the lungs. VSD is a hole in the wall that separates the left and right ventricles. Overriding aorta is a defect in which the aorta is positioned between the left and right ventricles, over the VSD. Right ventricular hypertrophy is the thickening of the right ventricle. The thickening is caused by the heart having to work harder because of the other defects. Truncus arteriosus is a defect of the great vessels. The aorta and pulmonary artery do not form as separate arteries. Instead, a large artery, called the truncus, comes from the heart. As the truncus leaves the heart, it may branch into arteries that carry blood to the body and to the lungs. Coarctation of the aorta is a narrowing of the aorta. It slows or blocks the flow of blood from the heart to the body. Anomalous pulmonary venous return is a defect in which one or more of the four pulmonary veins, which normally return oxygen-rich blood from the lungs to the heart, return to the wrong chamber in the heart.

Problems with development of the heart
Hypoplastic left heart syndrome is a combination of defects in which the left side of the heart does not develop properly. Defects usually include mitral atresia, aortic atresia, and a tiny left ventricle. Mitral atresia occurs when a solid sheet of tissue forms instead of the mitral valve, which separates the left atrium and the left ventricle. Aortic atresia occurs when a solid sheet of tissue forms instead of the aortic valve, which separates the left ventricle from the aorta. Single ventricle describes a group of heart defects in which only one ventricle is present instead of two. It can be a single right or a single left ventricle. The other ventricle is usually absent or very tiny. Hypoplastic left heart syndrome is an example of a single ventricle defect.Today, the outlook for an infant born with a heart defect is much better than it was 30 years ago. Rapid advances in infant and childhood surgery, better tests, and new medicines help most children with congenital heart defects. Many children born with more complex or severe heart defects now reach adulthood. Today, there are more than 1 million adults living with congenital heart defects.