Category Archives: Cardiac (Heart) Defects
Coarctation Of The Aorta (Aortic Coarctation)
Narrowing of the major blood vessel aorta at a point before where it is joined by the ductus arteriosis is termed as coarctation of the aorta.
- The narrowing of aorta significantly reduces the amount of blood reaching the lower half of the infant’s body.
- Heart murmurs, as well as a lower blood pressure in the legs when compared to that of the hands, are the usual symptoms, but some infants remain asymptomatic.
- The symptoms, when present, indicates this condition, but an echocardiography and a chest x-ray help confirm the diagnosis of aortic coarctation.
- Treatment involves surgical correction, and occasionally, drug therapy.
The flow of blood to the lower parts of the infant’s body is significantly decreased by aortic coarctation, resulting in measurable difference between the blood pressure in the hands and legs. The blood pressure in the legs becomes abnormally low, while the hands register an abnormally high blood pressure which persists in the upper parts of the body. A heart murmur indicating this condition also may be present. Coarctation should be treated; without proper treatment it causes high blood pressure and enlargement of the heart, eventually leading to heart failure. In children, coarctation of the aorta can cause bacterial endocarditis and brain hemorrhage. The aorta may rupture too. Other defects like aortic valve stenosis, and septal defects affecting the atria and ventricles, are usually present in infants who have aortic coarctation.
If coarctation is mild to moderate, it may remain asymptomatic. In rare cases, nose bleeds and headaches may be caused by the increased blood pressure in the upper parts of the body. Reduced blood flow to the legs may result in pain due to inadequate oxygen supply to the leg muscles during exercise.
If aortic coarctation is severe in the infant, the blood reaches the aorta through the ductus arteriosus which connects the pulmonary artery to the aorta at the point past the narrowing of the aorta. As long as the ductus arteriosus remains open, usually up to two weeks after birth, there will not be any symptoms of coarctation in the infant. When the alternate blood supply to the aorta stops with the closure of the ductus arteriosus, a sudden dramatic change takes place with almost complete loss of blood supply to the lower parts of the body, resulting in extremely low pressure. Potentially fatal heart failure too may occur.
When the doctor detects a heart murmur and differences in blood pressure or pulse between the infant’s arms and legs, coarctation is investigated. ECG, x-rays and echocardiography are tests used to diagnose the condition accurately.
If coarctation of the aorta is severe, it requires immediate emergency surgery to enlarge the narrowed portion of the aorta. As soon as the condition is detected, prostaglandin is administered to the newborn to reopen the ductus arteriosus, or to prevent its closure, so as to prolong the blood supply to the aorta. Alprostadil is a drug used for this purpose. Other drugs which strengthen the pumping action of the heart are also given. When the infant grows up, the surgery may have to be repeated. Instead of open heart surgery, balloon angioplasty may be done and a stent can be implanted to keep the aorta widened. If the symptoms due to aortic coarctation are mild, surgery is often postponed for three to five years.
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Transposition Of The Great Arteries (TGA)
When the aorta and the pulmonary artery are connected to the heart in reverse of their normal positions, the condition is termed as transposition of the great arteries (TGA).
- The reversed positions of the pulmonary artery and the aorta results in the reversal of the flow of oxygenated and deoxygenated blood; the oxygen-rich blood reaching the lungs instead of getting circulated to the body.
- Severe blue coloration of the infant’s skin (cyanosis) and breathing difficulty are the usual symptoms which are present at birth.
- The typical symptoms present at birth point to this condition; ECG, x-ray and echocardiography help in confirming the diagnosis.
- Surgical intervention within days of birth is necessary.
The deoxygenated blood returning to the heart normally gets emptied into the right atrium and then into the right ventricle from where it gets pumped out to the lungs via the pulmonary artery for oxygenation. When transposition of the great arteries is present, the oxygen-poor blood reaches the right ventricle as usual, but from there it gets pumped into the aorta instead of into the pulmonary artery going to the lungs. The aorta which normally supplies oxygenated blood to the other parts of the body thus receives deoxygenated blood instead. In the meantime, the oxygenated blood from the lungs returns via the pulmonary vein to the left atrium and into the left ventricle as usual. But, from the left ventricle it gets pumped back into the lungs again through the pulmonary artery, forming a closed loop between the heart and the lungs.
When infants are born with transposition of the great arteries (TGA), they may survive for a few days because of the existence of an opening between the left and right atria, called foramen ovale which allows the mixing up of the oxygenated and deoxygenated blood inside the heart. A blood vessel called ductus arteriosus, which connects the pulmonary artery to the aorta in the fetus, also allows some amount of mixing, as long as it remains patent. Often, in infants with transposition of the great arteries, a septal defect is present in the wall between the ventricles too. The limited oxygen supply which is made available to the body through the mixed blood may be sufficient for the infant to survive in the first few days after birth.
Symptoms such as bluish discoloration the body called cyanosis, and breathing difficulty, are usually present right from the time of birth. A physical examination of the infant, followed by x-ray, ECG, and an echocardiography, confirms the presence of transposition of the great arteries (TGA). Surgical correction as early as possible is necessary to save the life of the infant. Until the surgery can take place, a drug called alprostadil is given to keep the fetal circulatory pathways open. A minimally invasive procedure called balloon septostomy too may be performed for shunting the blood till surgery is performed. During surgery, the aorta is attached to the left ventricle and the pulmonary artery is connected to the right ventricle. The coronary arteries are reattached to the aorta after its repositioning.
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Congenital Pulmonary Valve Stenosis
When the pulmonary valve, which allows the blood in the right ventricle to pass into the pulmonary artery which leads to the lungs, is narrowed, it is referred to as pulmonary valve stenosis.
- The stenosis affects the valve in the right ventricle which allows blood to be pumped out into the pulmonary artery that carries it to the lungs.
- A heart murmur is the most common symptom, but in some cases, cyanosis may be present, and heart failure can occur.
- The symptoms lead to diagnosis, which is confirmed by echocardiography.
- The valve may be opened up by balloon valvuloplasty, but surgical reconstruction may be necessary in some cases.
Mild to moderate stenosis, which is more common, causes the right ventricle to work harder to get the blood pumped into the pulmonary artery through the narrowed valve opening. The blood is pumped at higher than normal pressure too. If the valve is severely narrowed, the right ventricle can pump out almost no blood into the lungs. Pressure builds up in the right ventricle, and when it becomes too high, the deoxygenated blood gets pumped through alternate pathways such as a septal defect in the atrial wall. This results in right-to-left shunting.
A heart murmur may be the only symptom displayed by most of the children who have congenital pulmonary valve stenosis. Cyanosis may be present in a few, and heart failure may occur in some. When the children grow older, fatigue and breathing difficulties may develop on exertion. Echocardiogram can confirm the condition, but sometimes, a procedure called cardiac catheterization is done to determine the severity and extent of stenosis.
Balloon valvuloplasty can successfully enlarge a valve with moderate stenosis, but if there are structural abnormalities, reconstructive surgery may be necessary. The fetal blood vessel ductus arteriosus is kept open with the administration of a prostaglandin drug like alprostadil, till surgical correction of the pulmonary valve can be done, or a an alternate route bypassing the valve can be created. This relieves severe cyanosis occurring due to pulmonary valve stenosis. When the infant grows older, surgery may have to be repeated.
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Congenital Aortic Valve Stenosis
When the aortic valve, which allows the oxygenated blood in the left ventricle to flow into the major artery aorta, is narrowed, it is referred to as aortic valve stenosis.
- The heart has to work more forcefully to pump the blood out into the aorta through the narrowed valve.
- A heart murmur is the usual symptom of aortic valve stenosis. Shortness of breath, pain in the chest, and fatigue, are the other symptoms that may occur in some cases.
- The typical heart murmur and the other symptoms lead to diagnosis.
- The valve has to be widened surgically, or in some cases, surgery is needed to replace the valve.
When the aortic valve is narrow, the left ventricle has to contract with higher than normal force to push the oxygenated blood into the aorta which supplies to the rest of the body. To maintain adequate blood supply, the heart pumps the blood at high pressure. Often, adequate amount of oxygenated blood does not reach the different parts of the body.
In most cases of congenital aortic valve stenosis, a typical heart murmur may be the only symptom present, especially in young children. As they get older, other symptoms such as shortness of breath and pain in the chest may be felt. Fatigue and occasional fainting may occur. Adolescents with aortic valve stenosis are at risk of sudden death, probably due to irregular heart rhythm resulting from the poor blood supply to the coronary artery which goes to the heart muscle. Irritability, pallor or paleness of skin, fast heart rate, sweating, extreme shortness of breath, and decreased blood pressure, are observed in some infants with aortic valve stenosis.
When a typical heart murmur is detected, or when a child has symptoms, congenital aortic valve stenosis is suspected and further investigations are conducted. Cardiac catheterization may help determine the extent and severity of stenosis.
Surgical options include widening of the valve, as well as valve replacement. Balloon valvulotomy is a procedure used to open up the valve surgically. Severe stenosis and associated symptoms may necessitate the implantation of an artificial valve. Since the risk of clot formation is high with artificial valves, an anticoagulant like warfarin should be taken by those who have them implanted. When heart failure results from aortic valve stenosis, immediate surgical intervention is necessary. Balloon valvuloplasty or surgical correction is done along with drug treatment.
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Fallot Tetralogy (Tetralogy of Fallot)
Fallot Tetralogy is characterized by four particular defects of the heart occurring together.
- The four defects of the heart occurring together results in poorly oxygenated blood circulating in the body.
- Heart murmur and cyanosis (bluish tint to the skin resulting from lack of oxygen in the blood) of varying degrees is the common symptom.
- Echocardiogram can diagnose this condition. The diagnosis is based on the results of an echocardiogram.
- Surgical correction is the treatment for tetralogy of Fallot.
A large opening in the ventricular septum (septal defect), along with the aorta displaced in such a way that the deoxygenated blood passes directly into the aorta from the infant’s right ventricle, results in right to left shunting of the blood. The right ventricular wall is thickened, and the flow of blood from the right ventricle into the pulmonary artery is restricted by the narrowing of the passage. All these four faults occur together in Fallot Tetralogy.
Infants who have Fallot tetralogy may have shortness of breath because of the decreased flow of blood from the right ventricle to the lungs. The pressure in the right ventricle increases as more blood gets collected there, and it causes this deoxygenated blood to pass into the left ventricle through the defect in the septum. This is termed as right-to left shunt. Cyanosis ranging from mild to severe is the usual symptom in infants. Sometimes, a potentially fatal condition called “tet” spells or hypercyanosis may suddenly develop in some infants, triggered by an activity such as a strained bowel movement or a bout of crying. Extreme shortness of breath develops, and the child may become unconscious. When a heart murmur indicates this condition, echocardiography is done to confirm it.
When a hypercyanotic spell occurs in an infant, oxygen should be administered immediately. A beta- blocker like propranolol and the drug morphine may quickly relieve symptoms. A knee-chest position may make breathing easier for the infant. It may be beneficial to administer phenylephrine or intravenous fluids to elevate resistance to the blood flow to the body. propranolol may be prescribed by the doctor to prevent future attacks too, till the infant undergoes surgery to correct the faults. In some infants, a condition called pulmonary atresia may be present in which the blood flow from right ventricle is completely blocked. They survive only if the ductus arteriosus remains open, hence alprostadil, a prostaglandin drug which helps keep it open, is given to them.
All infants who have Fallot Tetralogy require surgical correction of the faults, but how early they should undergo surgery depends on the severity of the symptoms. If the infant has severe symptoms which appear frequently, surgical correction is done as early as possible. When symptoms are mild, surgery is delayed till the infant is slightly older. A minimally invasive procedure called balloon valvulotomy may be done to maintain the blood flow to the lungs in the meantime. A balloon-tipped catheter threaded into the heart through a vein enlarges the valve opening by inflating the balloon. During surgery, the defect in the ventricular septum is repaired, and the pulmonary valve and the narrow passage out of the right ventricle are enlarged. Abnormal channels connecting pulmonary artery to the aorta are also blocked.
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Atrial and Ventricular Septal Defects
Incomplete septal separation between the right and left chambers of the heart, resulting in abnormal connections (hole in the wall) allowing the mixing up of oxygenated and deoxygenated blood, are referred to as atrial and ventricular septal defects.
- Septal defects occur in infants when the connections between the right and left chambers of the heart are not closed before birth.
- Most of the minor septal defects are asymptomatic and the holes may close spontaneously without any treatment.
- The typical symptoms lead to the diagnosis, and an echocardiography confirms it. Surgical closure may be necessary to treat serious septal defects.
Atrial septal defects occur in the wall separating the upper left and upper right chambers of the heart into which blood is emptied. A defect in the septum between the left and right ventricles which pump blood out of the heart is termed ventricular septal defect. These abnormal connections between the left and right chambers of the heart result in left-to-right shunting. Mostly, ventricular septal defects may close by the time the infants turn two. Defects in the atrial septum may close earlier, usually within the first year itself.
Septal defects may remain asymptomatic in infants and children. Children who are diagnosed with small septal defects should have echocardiography every year. If the defect is severe, some children may have fatigue, heart murmurs, and breathing difficulty. Occasionally, stroke may be the first indication of a septal defect. Children with atrial septal defects may have a worsening of the symptoms as they grow. Even heart failure can occur in a middle aged person with this condition.
Small ventricular septal defects may be asymptomatic or may have mild symptoms such as a heart murmur. They may close up eventually. However, a larger defect can result in severe symptoms in the infant. Ventricular septal defects result in more left-to-right shunting when compared to atrial septal defects, hence symptoms are also more severe.
It may cause heart failure and frequent infections in the lungs. Shunting usually increases in the first few weeks of life because of the typical way lung development progresses. The symptoms such as difficulty in feeding, rapid breathing, and sweating may become worse. Heart murmur may become louder too.
When symptoms indicate septal defects, echocardiography is done to confirm the condition. Diuretics like furosemide are used to treat the symptoms due to smaller septal defects. Captopril is a drug which lowers the resistance to the blood flow from the heart to the body. Large septal defects, and those which do not get closed in the early years of life, are surgically repaired.
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Patent Ductus Arteriosus (PDA)
When the fetal blood vessel ductus arteriosus which connects the pulmonary artery of the fetus to the aorta, which normally closes soon after birth, remains open in the infant, it is referred to as patent ductus arteriosus.
- When the fetal connection between the aorta and pulmonary artery remains open in the infant, it results in the abnormality patent ductus arteriosus.
- This condition may not cause any symptoms in most cases.
- A heart murmur, when investigated, may lead to the diagnosis of this condition.
- Drug treatment with indomethacin may close the connection; if it fails, surgical closure is necessary.
Patent ductus arteriosus causes left-to-right shunting of blood into the pulmonary artery, resulting in high blood pressure developing in the lungs due to the extra amount of blood flowing into the lungs. This may cause tissue damage in the lungs. This condition occurs more frequently in babies born prematurely.
Patent ductus arteriosus may be asymptomatic in most cases, and the condition in a newborn is suspected when a heart murmur is detected. The typical symptoms, when present, are cyanosis and breathing difficulty, which may either appear at birth or many weeks later.
A drug called indomethacin, which blocks prostaglandin production, is effective in closing the ductus arteriosus in 80% of the cases. This drug is administered as early as possible, usually within ten days of birth, as its effectiveness decreases with age. Prematurely born infants are benefitted more than infants born at full term. When patent ductus arteriosus is not resolved by repeated administration of indomethacin, the blood vessel connection is surgically closed.
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Overview Of Congenital Heart Defects
The incidence of congenital heart defects is found to be about one in 120 live births, but many of them are not serious conditions. The wall of the heart, valves in the heart or the blood vessels that arise from or lead to the heart may be having defects.
- Abnormalities in the formation of the valves or the wall of the heart may be responsible for the heart defects.
- Bluish discoloration of the skin known as cyanosis, breathing difficulty, growth retardation, inability to exercise, and heat failure are the apparent symptoms of congenital heart defects.
- Ultrasound scanning can detect most of the heart defects in infants.
- Severe heart defects require surgical intervention and correction, but minimally invasive procedures with a balloon-tipped catheter to open up or enlarge valves and vessels, as well as drug therapy with prostaglandins, may help in minor cases.
The blood circulation in fetus is different from that of young children and that of adults. In the normal circulatory pattern of children as well as adults, the blood in the veins is drained into the right atrium of the heart from which it enters the right ventricle. The contraction of the right ventricle pumps this venous blood into the pulmonary artery which takes it to the lungs for oxygenation. Exchange of gases take place in the alveoli or air sacs in the lungs, where the carbon dioxide in the venous blood is released and the oxygen from the fresh air is absorbed by the blood. The oxygenated blood is returned to the left atrium of the heart and then into the left ventricle. When the ventricle contracts, it gets pumped into the aorta from where various major arteries carry it to the different parts of the body. The fetus receives oxygenated blood from the placenta; hence most of the fetal blood takes a different circulatory route, with only some blood passing through the lungs.
In fetal circulation, the blood which drains into the right chambers of the heart is already oxygenated, and it mixes with the blood which drains into the left chambers of the heart after returning from the lungs. There is a septal opening connecting the left and right atria called foramen ovale through which this mixing of venous and arterial blood takes place. In the fetus, a blood vessel called ductus arteriosus connects the pulmonary artery containing venous blood to the major artery aorta arising from the heart, resulting in further mixing up of the blood. Since the placenta is carrying out the oxygenation of the venous blood, this mixing up of venous and arterial blood does not cause any problem in the fetus. However, after birth, the connection to the placenta is severed, and the oxygenation of the blood takes place in the lungs. If the deoxygenated venous blood reaching the heart continues to mix with the oxygenated blood returning to the heart from the lungs, it can significantly reduce the amount of oxygen reaching the various tissues through the arteries. The ductus arteriosus and the foramen ovale normally close up soon after birth to prevent this condition. If they remain open, it is regarded as a heart defect.
Congenital heart defects result in abnormal circulatory patterns. Either rerouting of the blood flow known as shunting, or blockage to the blood flow may occur due to defects in the blood vessels or the heart valves.
Deoxygenated blood which has returned to the right chambers of the heart gets mixed with oxygenated blood pumped out to the body from the left side of the heart due to right-to-left shunting. This causes the deoxygenated blood to circulate in the body causing a bluish discoloration known as cyanosis. The severity of cyanosis depends on the amount of oxygen-poor blood mixing with oxygenated blood being pumped out to the body.
The oxygenated blood from the lungs and the deoxygenated venous blood returning to the heart get mixed up when shunting occurs. It affects the efficiency of blood circulation which provides oxygen to all the tissues in the body. Heart failure may eventually develop as the heart becomes unable to pump adequate amount of oxygenated blood to meet the body’s requirements. When the oxygen-rich blood which is pumped at a higher pressure mixes with the blood going to the lungs, the pulmonary artery as well as the lungs gets damaged by the high pressure.
When heart failure develops, blood may accumulate in other parts of the body, especially in the lungs. Heart failure may also result when blood flow into the heart is blocked and from poor pumping of the heart due to the weakness of the heart muscle in some infants.
Sometimes, blockages occur in the heart valves or in any of the blood vessels carrying blood from the heart. Pulmonary artery stenosis where the blood vessel leading from the heart to the lungs is narrowed, and pulmonary valve stenosis in which the valve allowing the blood flow into the pulmonary artery is narrowed, may restrict blood flow from the heart into the lungs for oxygenation. Aortic valve stenosis or a blockage in the aorta known as coarctation may impede the flow of oxygenated blood to the other parts of the body.
Symptoms and Diagnosis
Many congenital heart defects remain asymptomatic and are not detected in infants in spite of the physical examination conducted after birth. The symptoms of certain mild defects may not appear till the person reaches middle age. Reduced weight gain and growth retardation may be caused by heart defects which result in poor blood supply to the body, as oxygen-rich blood is essential for normal development. Activity demands extra oxygen supply, and children with heart defects may not be able to indulge in vigorous play or exercise. Symptoms like cyanosis and breathing difficulty may appear on exertion. If heart failure results from defects in the heart, fluid collection in the lungs and rapid heartbeat are the usual symptoms. Certain heart defects like patent foramen ovale in the atrial septum increase the risk of clot formation in the heart. If a clot travel to an artery supplying the brain and blocks it, stroke may result. Abnormal circulatory patterns in the heart due to heart defects cause abnormal sounds known as murmurs which can be detected by a stethoscope. However, all heart murmurs occurring in childhood are not due to heart defects.
Ultrasonography test of the fetus may reveal many of the congenital heart defects present even before the infant is born. Typical heart murmurs and symptoms in a newborn alert the doctors to possible heart defects, which are investigated further to diagnose the exact abnormality.
The same diagnostic techniques used for detecting heart problems in adults are used to diagnose congenital heart defects in infants and children. A physical examination and feedback from parents and caregivers of the infant may indicate the nature of the defect to the doctor. An x-ray of the chest, ECG and echocardiography can diagnose most of the heart defects. A minimally invasive procedure called cardiac catheterization may be necessary to detect certain abnormalities which are not easily detected by the other tests. This test is sometimes conducted to determine more accurately the exact nature and extent of a defect detected by echocardiography.
Treatment
Open-heart surgery may be required to correct most of the serious congenital heart defects. The surgery is scheduled depending on the severity of the symptoms and the infant’s condition. Some severe cases may need immediate surgical intervention, but whenever possible, surgery is delayed till the infant grows older.
Constrictions in the blood vessels and narrowed heart valves can be enlarged by minimally invasive procedures in which a thin tube called catheter is threaded through a suitable blood vessel to reach the location of the defect. A tiny balloon at the tip of catheter can be inflated to enlarge the narrowed area. This procedure is termed balloon angioplasty when it is used to widen a narrowed blood vessel, and balloon valvuloplasty when used to open up narrowed heart valves. Minor defects are repaired using these procedures to avoid the risks involved in a major surgery and in giving general anesthesia to the infant, in spite of the fact that open-heart surgery is more effective in correcting most defects.
A severe block in the pulmonary artery or the aorta can be temporarily relieved by creating a shunt to maintain blood circulation. An opening in the atrial septum may be created by a procedure called balloon septostomy. Administering prostaglandins may help the fetal blood vessel ductus arteriosus to remain open, allowing the flow of blood between the pulmonary artery and the aorta. Heart transplant is an option when attempts at surgical correction fail, but it is often limited by the unavailability of suitable donor hearts.
Endocarditis or infections affecting the heart and heart valves are more common in children with serious congenital heart defects. They should take antibiotic therapy before undergoing surgical procedures and treatments.
Most common congenital heart defects are:
- Patent ductus arteriosus
- Atrial septal defect
- Ventricular septal defect
- Fallot tetralogy
- Transposition of the great arteries.
- Aortic valve stenosis
- Pulmonary Valve stenosis
- Coarctation of the aorta
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