Congenital Heart Diseases

Two to three babies of every 1,000 show the first signs of a heart disorder during the first year of life. The precise cause of a congenital heart disorder is rarely found, although, as a rule, multifactorial inheritance seems to be responsible. Some chromosome abnormalities, such as the one that causes Down syndrome, also are associated with heart defects. Infections such as German measles, contracted by the mother during the first 2 months of pregnancy, also increase the risk of congenital heart defects. Certain drugs, vitamin deficiencies or excessive exposure to radiation are among other environmental factors known to be associated with such defects.

The term blue baby refers to the infant born with a heart impairment that prevents blood from getting enough oxygen. Because blood is low in oxygen dark bluish red, it imparts a blue tinge to the skin and lips.

Heart abnormalities may occur singly or in combination. There may be, for example a hole in the walls separating the right and left heart chambers or a narrowing of a valve or blood vessel which obstructs blood flow, or a mixup in major blood vessel connections or a combination of all of these.

Diagnosis

A skilled cardiologist often can make a reasonably complete diagnosis on the basis of a conventional physical examination including visual inspection of the infant’s general condition, blood pressure reading, X ray, blood tests, and electrocardiogram and echocardiography.

For more complex diagnosis, the physician may call for either angiography or cardiac catheterization. The former, a variation of coronary arteriography, allows direct X-ray visualization of the heart chambers and major blood vessels. In cardiac catheterization, a thin plastic tube or catheter is inserted into an arm or leg vein. While the physician watches with special X-ray equipment, the tube is advanced carefully through the vein until it reaches the heart chambers, there to provide information about the nature of the defect.

Treatment

From these tests, the cardiologist together with a surgeon can decide for or against surgery. Depending on the severity of the disease, some conditions may require an immediate operation, even on days-old infants. In other conditions, the specialists may instead recommend waiting until the infant is older and stronger before surgery is undertaken. In a number of instances, the defect may not require surgery at all.

Open-heart surgery in infants with inborn heart defects carries a higher risk than does the same surgery in older children. Risks must be taken often, however, because about one third will die in the first month if untreated, and more than half within the first year.

Refinements in surgical techniques and postoperative care have given surgeons the confidence to operate on infants who are merely hours old with remarkable success. Specially adapted miniature heart-lung machines may also chill the blood to produce hypothermia, or body cooling. This slows metabolism and reduces tissue oxygen needs so that the heart and brain can withstand short periods of interrupted blood flow.

A good deal has been learned, too, about the delicate medical management required for infants during the surgical recovery period. All of this accounts for the admirable record of salvage among infants who would have been given up for lost only a few years ago. Some of the common congenital heart disorders are described:

Ventricular Septal Defect (VSD)

• Ventricular septal defect is the most common heart malformation, accounting for 25 percent of the cases of congenital heart disease. The infant born with this defect has an opening between the lower chambers (ventricles) of its heart so that there is an increased blood flow, under high pressure, to the lungs.
• The symptoms vary depending on the size of the defect. Most children have a small opening that does not produce noticeable symptoms. The problem may be discovered during a routine stethoscopic examination when the physician may detect a slight murmur. Babies born with large defects develop pulmonaryhypertension, feeding difficulties, profuse perspiration, poor growth rates, recurrent pulmonary infections, and cardiac failure in early infancy.
• Treatment depends on the size of the defect. Approximately 30 to 50 percent of small defects close spontaneously during the first year of life. Many children have no symptoms and no apparent heart damage.
• Treatment for infants with symptoms is aimed at controlling the heart failure with drugs. If this is unsuccessful, an operation to close the defect should be done before as early as possible.

Atrial Septal Defect

• Atrial septal defect is an opening high in the heart between the upper chambers (atria); it produces abnormal blood flow. It is more common in female infants than in males, and it often occurs in children with Down syndrome.
• The affected children frequently have no symptoms.
• Surgical closure is the recommended treatment, usually between the ages of 3 and 5 years (preschool age).

Patent Ductus Arteriosus

• The ductus arteriosus is a vessel that leads from the pulmonary artery to the aorta. Normally, this closes immediately after birth. When it does not, blood flows between the pulmonary artery and the aorta; this condition is called patent ductus arteriosus. In babies who are born prematurely, the ductus has not had time to close. In a full term infant, failure to close is a congenital malformation.
• Patent ductus arteriosus occurs more often in female infants, in children born at high altitude, and in the offspring of women who had German measles (rubella) during the first 3 months of pregnancy.
• If the ductus is small, there are often no symptoms. A large ductus will produce a heart murmur, hypertension, and growth retardation.
• In the premature infant, the ductus often closes spontaneously within weeks or months. In the full term infant or the premature infant whose ductus fails to close, operation is necessary, usually between the first and second years of life.
• In some patients, this ductus can be closed also by special coils that are placed using cardiac catheterization without the need for surgery

Coarctation Of The Aorta

• Coarctation (constriction) of the aorta results in increased blood pressure above the obstruction. There are usually no symptoms. However, heart failure may develop because of other associated heart abnormalities.
• In the absence of symptoms, the obstruction should be surgically relieved between the ages of 2 and 5 years if it is determined to be significant; this will help prevent future complications.

Tetralogy Of Fallot

• Tetralogy of Fallot consists of a large ventricular septal defect, obstruction of blood flow from the heart’s right ventricle to the lung (pulmonary) arteries, and a shift of the aorta to the right side of the heart. The right ventricle also is enlarged. The result is decreased blood flow to the lungs.
• The main symptom of this disorder is a bluish cast to the skin (cyanosis), although this may not always be present at birth. The symptoms of tetralogy of Fallot often begin slowly during the first year of life. Sometimes, however, the problem is apparent at birth.
• Treatment is geared toward providing an immediate increase in pulmonary blood flow. Infants with this disorder should be in specially equipped neonatal centers. Corrective open heart operation is the usual treatment once your child is 6 months. However, occasionally an operation is performed during infancy to improve blood flow to the lung and to decrease cyanosis

Pulmonary Stenosis

• Pulmonary stenosis is an obstruction of blood flow from the heart to the pulmonary artery. With mild or moderate obstruction, there are often no symptoms. The newborn with a severe obstruction has a bluish cast to the skin and shows signs of heart failure.
• Congestive heart failure occurs in the worst cases during the first month of life. Children with mild to moderate stenosis can lead a normal life but they should be under the regular care of a physician. Those with more severe stenosis require operation and sometimes balloon valvotomy of this narrowed valve.

Aortic Stenosis

• Aortic stenosis is a narrowing of the valve through which blood leaves the heart to enter the aorta. It is more common in male infants and accounts for 5 percent of cardiac malformations.
• Severe stenosis generally is detected in early infancy. However, most children have no symptoms and the problem is found during a routine examination when the physician hears a heart murmur.
• Operation or balloon valvotomy is needed for severe stenosis.
• Children with mild or moderate obstruction should remain under medical care because of the possibility of the obstruction increasing in severity.

Transposition Of The Great Vessels

• Transposition of the great vessels is a complex defect in which the two arteries arising from the heart are reversed. Blood returning to the heart from the body is pumped back to the body without passage through the lungs. Infants with transposition are blue (severely cyanotic) and must have immediate medical care.
• Several surgical procedures are available to relieve the problem, one of them is called the arterial switch operation which is usually performed during the first 2 weeks of life. This operation aims at reversing the positions of the aorta and pulmonary arteries back to normal.