Any kind of structural defect occurring in the heart, at the time of birth is called a congenital heart defect. They are the commonest type of heart defects and occur while the foetus is implanted in the uterus. Out of every 1,000 children at least 8-10 are reported to have this defect. Additional deaths are reported due to congenital heart diseases in the early stages of infancy rather than any other birth deformity. Symptoms due to congenital heart defects may be apparent at birth, during childhood, but in some cases individuals remain asymptomatic until adulthood. About 500,000 adults in the U.S. have heart ailments due to congenital heart diseases.
Shortly after conception the heart of a foetus begins to develop. During the course of development defects pertaining to anatomy can occur which involve walls of the heart, the valves of the heart and the arteries and veins near the heart. Due to these structural defects the normal course of circulation of blood is disturbed. As a result of these abnormalities the flow of blood slows down, goes in a wrong direction and to the wrong place, or gets blocked completely. Diseases generating from these defects are called congenital heart diseases out of which some get cured in the due course of time while others need to be treated .Diseases caused due to Congenital heart defects have been broadly classified as cyanotic (lacking in oxygen, blue discoloration) and non-cyanotic categories. The diseases in cyanotic category include ebstein’s anomaly, return of the pulmonary venous blood, fallot tetralogy and pulmonary artesia to name some. While the common diseases in the non-cyanotic category include septal defect of atria and ventricles, aortic coarctation, stenosis of aorta and endocardial cushion defect to name some. Congenital heart diseases may or may not be accompanied with other maladies. A range of genetic disorders and chromosomal aberrations like Marfan syndrome, trisomy of 13th chromosome can lead to these defects. Also syndromes like Noonan and Down’s syndrome have been known to result in defects pertaining to the structural development of the heart.
Many types of congenital heart defects have been known to be present, at times combinations of multiple defects leads to a complex defect and serious abnormalities. Some common simple congenital defects include
Septal defects: They are popularly called the holes in the heart. Wall that separates the left and the right chambers of the heart is called the septum. When an infant is born with an aperture in the septum it permits the blood in the respective chambers to mix. So the oxygenated blood mingles with the deoxygenated blood and can lead to severe complications.
Atrial septal defect (ASD) : Presence of an aperture in the septum that separates the two auricles, right and the left leads to this defect. This permits the oxygenated blood to flow from the left auricle into the right auricle in place of left ventricle. In case of small ASDs normal functioning of the heart is not affected and therefore do not need a treatment. Children may not even produce symptoms in such cases and they get closed on their own during gradual growth of the native but large and medium ASDs can be worrisome and require an aid.
Ventricular septal defect (VSD) : As the name indicates ,the presence of a hole in the wall or septum separating the ventricles. This defect again leads to the mingling up of oxygenated blood from the left ventricle into that in the right ventricle instead of flowing into aorta. Small and minor holes can repair on their own but in case of medium and large ones heart has to exert more pressure to pump blood into aorta, against the force of gravity. This eventually may also lead to a heart failure and pulmonary arterial hypertension.
Narrowed Valves: Even due to structural, functional defects and disposition of the valves obstruction in the normal circulation of blood occurs. Valves are small structures which are chiefly concerned with regulating the direction of flow of the blood. They open in one direction and prevent the back flow of the blood. Defects related with valves include Stenosis (the valves do not open entirely and therefore heart has to work harder to pump the blood), Atresia (in which valve is not formed properly leaving to passage for blood), Regurgitation(when the valve doesn’t close properly and allows the blood to fall back)
Valves are flap like structures present between the auricles and ventricle and in the inner walls of pulmonary vein and aorta. Commonest valve defect, is the pulmonary stenosis which arises due to pulmonary valve narrowing. Depending on its severity it may produce symptoms. In mild cases no sign other than heart murmur is produced as a symptom. But in case of severe defect it can also lead to cyanosis during which the skin, finger nails, lips gain a bluish tint because the level of oxygen in the blood leaving heart is below normal.
Unless very acute the congenital defects produce no symptoms and therefore are not detected easily. However, certain heart defects do produce symptoms especially in new born babies which include rapid breathing, cyanosis (appearance of a bluish tint on the skin) , perpetual fatigue, poor circulation of blood. Interestingly they are not characterised with the commonly occurring pain in the chest region but certain sounds called heart murmurs are evident. Normal growth of an infant is hampered due to these defects. In older children since heart is inefficient in pumping blood strongly throughout the body, it can lead to a heart failure. Heart failure is characterised by onset of fatigue with exercise, shortness of breath, fluid build up in lungs, ankle, feet and legs.
Though, the cause leading to these congenital defects is still a matter of debate and research. Investigations reveal that alcohol, retinoic acid for acne, infections etc during pregnancy can contribute to some congenital heart problems. Inheritance of these defects has also been reported through heredity, a child is more likely to have it in case one of the parents or close relatives suffers from the ailment. Chromosomal aberrations and other genetic defects have also been known to contribute to congenital heart defects.
Special tests are performed to detect the defects which include a physical exam, during which rapid breathing, cyanosis, delayed growth are certain symptoms which are looked for. Other commonly employed tests include Echocardiogram in which sound waves are used to create a moving picture of a child’s heart. The test allows in determining any difficulty in the functioning of the heart. In case a congenital heart defect is suspected during pregnancy then a foetal cardiogram can be recommended in the fourth or the fifth month of pregnancy. This reflects the state of the heart while the baby is in the womb and allows the doctor to move a step ahead in planning the treatment of the baby. .
Electrocardiogram is another popular test conducted which records the electrical activity and rhythmic movements of the heart. Patterns furnished during the test help diagnose the problem. X ray of the thoracic region also shows enlarged heart or lungs with fluid accumulation which are prominent signs of heart failure. Pulse oximetry is executed to measure the amount of oxygen in the blood. With the help of a sensor placed at an individual’s fingertip or toe this is reflected on a computer screen.Cardiac catheterization during which a catheter is introduced in a vein in the arm, groin, neck region reaching heart. A dye is injected into which follows the course of circulation highlighting the anomalies.
Post diagnoses the treatment can be procured through different techniques. Treatment varies according the age, general health and the growth of an individual. It can be simple or very complex involving the use of catheters or surgeries or medication to repair the defects. Surgeries involving the use catheters are much easier and there is no need to open the chest. In case of rectifying the atrial septal defects catheter is made to reach the septum through a vein. It has a tiny umbrella like device inside it and when it reaches the specific spot the device is pushed into the aperture such that it plugs the aperture and later the catheter is withdrawn the aperture. In pulmonary valve stenosis the catheter is made to reach the pulmonary valve through a vein, where the tiny balloon shaped device at the end of the catheter is inflated to push apart the flaps of the valves and is then deflated, later the catheter is withdrawn .It is done to narrow the valves.
In case of serious defects open heart surgeries are also performed during which the holes are closed with stitches or patches, heart valves are replaced. In case the heart defects are too complex then heart transplant is also administered.
Congenital defects also envisage the onset of endocarditis in many. Certain measures adopted to protect from the threat of the same are: good care should be taken to prevent the teeth and gums from infections, a doctor should be seen in case of recurring fever, aches and sore throat, antibiotics should be taken as per prescription before undergoing any invasive test which may involve bleeding.