Congenital heart defect

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(Redirected from Heart defects)

A congenital heart defect (CHD) is a defect in the structure of the heart
and great vessels of the newborn. Most heart defects either obstruct blood flow in the heart or vessels near it or cause blood to flow through the heart in an abnormal pattern, although other defects affecting heart rhythm (such as long QT syndrome) can also occur. Heart defects are among the most common birth defects, and are the leading cause of birth defect-related deaths.
Contents

1 Overview
2 Epidemiology
3 Aetiology
4 Major categories
4.1 Patent ductus arteriosus
4.2 Hypoplasia
4.3 Obstruction defects
4.4 Septal defects
4.5 Cyanotic defects
4.6 Other defects
5 Signs and Symptoms
6 Treatment
7 Defects
8 References
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Congenital heart defects can be broadly categorised into two groups, acyanotic heart defects ('pink' babies) and cyanotic heart defects ('blue' babies).
Epidemiology
Slightly less than 1% of all newborn infants have congenital heart disease. Eight defects are more common than all others and make up 80% of all congenital heart diseases, whereas the remaining 20% consist of many independently infrequent conditions or combinations of several defects. Ventricular septal defect (VSD) is generally considered to be the most common type of malformation, accounting for about 1/3 of all congenital heart defects.
The incidence is higher when a parent or a sibling has a heart defect (4-5%), in stillborns (3-4%), abortuses (10-25%), and premature infants (2%).
The number of adults with problems connected to a congenital heart defect is rising and is passing the number of children with congenital heart defects in most western countries. This group is called GUCH patients.
Aetiology
The cause of most congenital heart defects is unknown.
Where a cause is known, it may be of a multifactorial origin and/or a result of genetic predisposition and environmental factors.
Known genetic causes of heart disease includes chromosomal abnormalities such as trisomies 21, 13, and 18, as well as a range of newly recognised genetic point mutations, point deletions and other genetic abnormalities as seen in syndromes such as CATCH 22, familial ASD with heart block, Alagille syndrome, Noonan syndrome, and many more.
Known antenatal environmental factors include maternal infections (Rubella), drugs (alcohol, hydantoin, lithium and thalidomide) and maternal illness (diabetes mellitus, phenylketonuria, and systemic lupus erythematosus).
Major categories
Patent ductus arteriosus
Main article: Patent ductus arteriosus
The ductus arteriosus is a temporary pathway in the foetal heart between the pulmonary artery and aorta, which allows blood to bypass the fetus' nonfunctioning lungs until birth. Normally, the ductus closes within a few hours or days of birth; when it does not, the result is patent ductus arteriosus. This defect is common in premature infants but rare in full-term infants.
Hypoplasia
Main article: Hypoplastic left heart syndrome
Hypoplasia can affect the heart, which typically results in the failure of either the right ventricle or the left ventricle to adequately develop, leaving only one side of the heart capable of pumping blood to the body and lungs. Hypoplasia of the heart is rare but is the most serious form of CHD; it is called hypoplastic left heart syndrome when it affects the left side of the heart and hypoplastic right heart syndrome when it affects the right side of the heart. In both conditions, the presence of a patent ductus arteriosus (and, when hypoplasia affects the right side of the heart, a patent foramen ovale) is vital to the infant's ability to survive until emergency heart surgery can be performed, since without these pathways blood cannot circulate to the body (or lungs, depending on which side of the heart is defective). Hypoplasia of the heart is generally a cyanotic heart defectObstruction defects
Obstruction defects occur when heart valves, arteries, or veins are abnormally narrow or blocked. Common obstruction defects include pulmonary valve stenosis, aortic valve stenosis, and coarctation of the aorta, with other types such as bicuspid aortic valve stenosis and subaortic stenosis being comparatively rare. Any narrowing or blockage can cause heart enlargement or hypertension.
Septal defects
The septum is a wall of tissue which separates the left heart from the right heart. It is comparatively common for defects to exist in the interatrial septum or the interventricular septum, allowing blood to flow from the left side of the heart to the right, reducing the heart's efficiency. Ventricular septal defects are collectively the most common type of CHD, although approximately 30% of adults have a type of atrial septal defect called patent foramen ovale. Septal defects may or may not cause cyanosis depending on the severity of the defect.
Cyanotic defects
Cyanotic heart defects are called such because they result in cyanosis, a bluish-grey discoloration of the skin due to a lack of oxygen in the body. Such defects include persistent truncus arteriosus, total anomalous pulmonary venous connection, tetralogy of Fallot, transposition of the great vessels, and tricuspid atresia.
Other defects
Ebstein's anomaly
Brugada syndrome
Marfan syndrome
DiGeorge Syndrome
Signs and Symptoms
Symptoms and signs are related to the type and severity of the heart defects. Some children have no signs while others may exhibit shortness of breath, cyanosis, chest pain, syncope, sweating, heart murmur, respiratory infections, underdeveloping of limbs and muscles, poor feeding, or poor growth. Most defects cause a whispering sound, or murmur, as blood moves through the heart causing some of these symptoms. All of these symptoms occur at a young age of a child or infant which is typically found during a physical examination.
Treatment
Sometimes CHD improves with no treatment necessary. At other times the defect is so small and does not require any treatment. Most of the time CHD is serious and requires surgery and/or medications. Medications include diuretics which aid the baby in eliminating water, salts, and digoxin, which aids in strengthening the contraction of the heart. This slows the heartbeat and removes some fluid from tissues. Some defects require surgical procedures to repair as much as possible to restore circulation back to normal. In some cases, multiple surgeries are needed to be performed to help balance the circulation. Interventional cardiology now offers patients minimally invasive alternatives to surgery. Device closures can now be treated with a standard transcatheter procedure using a closure device mounted on a balloon catheter. Equally stenosis can be treated using a balloon dilation procedure to dilate the obstruction during cardiac catheterization.[1]
Defects
Aortic stenosis
Atrial septal defect (ASD)
Atrioventricular septal defect (AVSD)
Coarctation of the aorta (CoA)
Dextrocardia
Ebstein's anomaly
Hypoplastic left heart syndrome (HLHS)
levo-Transposition of the great arteries (l-TGA)
Partial anomalous pulmonary venous connection (PAPVC)
Patent ductus arteriosus (PDA)
Pulmonary atresia
Pulmonary stenosis
Tetralogy of Fallot (ToF)
Total anomalous pulmonary venous connection (TAPVC)
dextro-Transposition of the great arteries (d-TGA)
Tricuspid atresia
Truncus arteriosus
Ventricular septal defect (VSD)
This is an incomplete list, which may never be able to satisfy certain standards for completeness. Revisions and sourced additions are welcome.

References
^ W. Hellenbrand (2006). Non-surgical Alternatives in the Treatment of Congenital Heart Defects.