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Congenital Defects
Each year about 25,000 babies in the United States are born with a congenital heart defect (see Birth Defects). A wide variety of heart malformations can occur. One of the most common abnormalities is a septal defect, an opening between the right and left atrium or between the right and left ventricle. In other infants, the ductus arteriosus, a fetal blood vessel that usually closes soon after birth, remains open. In babies with these abnormalities, some of the oxygen-rich blood returning from the lungs is pumped to the lungs again, placing extra strain on the right ventricle and on the blood vessels leading to and from the lung. Sometimes a portion of the aorta is abnormally narrow and unable to carry sufficient blood to the body. This condition, called coarctation of the aorta, places extra strain on the left ventricle because it must work harder to pump blood beyond the narrow portion of the aorta. With the heart pumping harder, high blood pressure often develops in the upper body and may cause a blood vessel in the brain to burst, a complication that is often fatal. An infant may be born with several different heart defects, as in the condition known as tetralogy of Fallot. In this condition, a combination of four different heart malformations allows mixing of oxygenated and deoxygenated blood pumped by the heart. Infants with tetralogy of Fallot are often known as “blue babies” because of the characteristic bluish tinge of their skin, a condition caused by lack of oxygen.
In many cases, the cause of a congenital heart defect is difficult to identify. Some defects may be due to genetic factors, while others may be the result of viral infections or exposure to certain chemicals during the early part of the mother’s pregnancy. Regardless of the cause, most congenital malformations of the heart can be treated successfully with surgery, sometimes performed within a few weeks or months of birth. For example, a septal defect can be repaired with a patch made from pericardium or synthetic fabric that is sewn over the hole. An open ductus arteriosus is cut, and the pulmonary artery and aorta are stitched closed. To correct coarctation of the aorta, a surgeon snips out the narrowed portion of the vessel and sews the normal ends together, or sews in a tube of fabric to connect the ends. Surgery for tetralogy of Fallot involves procedures to correct each part of the defect. Success rates for many of these operations are well above 90 percent, and with treatment most children with congenital heart defects live healthy, normal lives. |
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