Medical Definition of CHD
CHD: Congenital heart disease, a malformation of the heart or the large blood vessels near the heart. The term "congenital" speaks only to time, not to causation; it means "born with" or "present at birth."
Congenital heart disease is the most frequent form of major birth defects in newborns affecting close to 1% of newborn babies (8 per 1,000). This figure is an underestimate since it does not include some common problems, namely:
- Patent ductus arteriosus in preterm babies (a temporary condition)
- Bicuspid (two cusps) aortic valve (the aortic valve usually has three cusps or flaps)
- Mitral valve prolapse (drooping of a heart valve)
- Peripheral pulmonary stenosis (narrowing of the lung vessels well away from the heart)
There are a great many types of congenital heart disease. Here is an outline of the major categories of congenital heart disease and some of the more prominent entities within those categories.
Detour defects within the heart: Defects may cause blood to take an abnormal route through the heart, passing directly between the right and left sides of the heart. This occurs when there is a defect in the wall (the septum) that normally separates the right and left sides of the heart. There is "a hole in the heart." The two most common types of septal defect are:
- Atrial septal defect (ASD)
- Ventricular septal defect (VSD)
Less common types of CHD with altered routes of blood flow include:
- Eisenmenger's complex
- Atrioventricular (A-V) canal defect (also called an endocardial cushion defect)
Detour defect outside the heart: Patent ductus arteriosus (PDA) is a special type of a blood routing problem located outside the heart. The ductus arteriosus is a prenatal shunt between the pulmonary artery and the aorta that remains open (patent) after birth, letting blood that should flow through the aorta to the body return to the lungs.
Obstructive defects: A number of types of CHD obstruct blood flow within the heart or the great vessels near it. They do so via a narrowing that partly or completely blocks the flow of blood. The narrowing (a stenosis) can occur in heart valves, arteries or veins. The three most common forms of CHD with obstructed blood flow are:
- Pulmonary (valvular) stenosis
- Aortic stenosis
- Coarctation of the aorta
Less common forms of CHD with obstructed blood flow include:
- Bicuspid aortic valve
- Subaortic stenosis
- Ebstein's anomaly
Cyanotic defects ("blue babies"): Some types of CHD cause cyanosis (bluing). The blood pumped to the body has less-than-normal amounts of oxygen. This results in cyanosis, a bluish discoloration of the skin. Types of cyanotic forms of CHD include:
- Tetralogy of Fallot
- Transposition of the great arteries
- Tricuspid atresia
- Truncus arteriosus
- Total anomalous pulmonary venous return
- Pulmonary atresia
Hypoplastic heart defects: Part of the heart may selectively be underdeveloped or hypoplastic, as in:
- Right heart hypoplasia
- Left heart hypoplasia
Other developmental heart defects: A number of other defects in heart development can occur, such as:
- Single ventricle (There is only one ventricle)
- Double outlet right ventricle (Both the aorta and pulmonary artery emanate from the right ventricle)
Alternative names for congenital heart disease include: congenital heart defect, congenital heart malformation, congenital cardiovascular disease, congenital cardiovascular defect, and congenital cardiovascular malformation.
For a more complete treatment of this topic, see the full-length article on Congenital Heart Disease.
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