Congenital Heart Diseases

Congenital heart diseases are heart defects present at birth; they are the result of abnormal heart development before birth. In the beginning, the heart is nothing more than a simple pulsatile tube, which has to rotate, cavitate, form valves, in order to become the complex organ it is at birth. So, during the embryonic development, there are many chances for disorders to occur.

These disorders may appear in the form of abnormal holes between the chambers, incorrect connections between chambers and vessels, valves which do not function or open correctly, and others. Congenital heart diseases affect a bit less than 1% of all children (about 8 of every 1,000 infants).

The causes are rather difficult to determine and are still under investigation by doctors and scientists. So far, doctors have been able to determine some conditions and factors that put a child at risk of developing some form of congenital heart defect.

Among these, there are factors that can be controlled, such as the health condition of the mother and factors that cannot, such as hereditary factors.

Drugs, chemicals and infections of the mother during pregnancy are also causes of congenital heart abnormalities of the newborn. Maternal alcohol use can be very harmful, as well as the use of retinoic acid (for the treatment of acne), or of any street drugs. Some medication may also put the infant at risk, so doctors should be made aware of a woman's pregnancy before they describe any drugs. Apart from alcohol, drugs and chemicals, the mother should avoid exposure to infections. Rubella (German measles) is particularly dangerous, so any mother-to-be should have her immune status for Rubella evaluated early in the pregnancy. HIV infections and diabetes in the mother can also lead to the baby's developing congenital defects. Toxoplasmosis, an infection passed through contact with cat feces is another risk factor for the infant.

There may also be hereditary factors involved. There are cases when more than one child in a family has a congenital heart defect. Parents who have had one child with a congenital heart abnormality are at an increased risk of having another child with such a defect; this risk increases, in these cases, from the 1 in 1000 range to 1 in 20, and can be greater with certain forms of congenital disease that are frequently transmitted from parents to children, although chromosome defects are only found in about 10% of heart defect cases.

Some congenital heart defects may be a part of genetic and chromosomal syndromes, such as Down syndrome, trisomy 13, Turner's syndrome, Noonan syndrome or Marfan syndrome. However, the majority of them appear as an isolated defect, and not associated with other diseases.

Congenital heart abnormalities can occur either as a single defect or in combinations. The most commonly diagnosed congenital heart defect is the ventricular septal defect (VSD) (approximately 1/3 of all cases), followed by atrial septal defects (ASD) and patent ductus arteriosus (PDA). All these are types of non-cyanotic congenital heart diseases. Cyanotic heart defects are associated with a blue discoloration of the skin due to a relative lack of oxygen.

The aortic stenosis and the pulmonic stenosis are also types of non-cyanotic congenital heart disease, while the hypoplastic left/right syndrome, the tetralogy of Fallot, tricuspid atresia, truncus arteriosus, Ebstein's anomaly, the total anomalous pulmonary venous return and the transposition of the great vessels are all cyanotic types of congenital heart defects.

Some of these congenital heart diseases can be treated with medication alone, while others require single or multiple surgery. Congenital heart diseases are responsible for more deaths in the first year of life than any other type of birth defects, this is why they need to be discovered early and followed carefully. Prenatal care of expectant mothers is essential, as many of these defects can be discovered on routine ultrasound examinations, while the baby is still in utero. The appropriate medical personnel (pediatric cardiologist cardiothoracic surgeon, etc) can be present at birth, increasing the baby's chances for survival.

However, not all types of congenital heart defects are noticeable at birth; their effects may only be obvious later. For example, in the case of the coarctation of the aorta, the effects may not be present for many years; in the case of the ventricular septal defect, if the lesions are small, they may never cause problems and the patient may lead a normal life and have normal physical activity.