A baby's heart begins to develop at conception, and is completely formed by eight weeks into the pregnancy. Congenital heart defects happen during these crucial first eight weeks of the baby's development. Often, congenital heart defects are a result of one of these crucial steps not happening at the right time, leaving a hole where a dividing wall should have formed, or a single blood vessel where two ought to be. In most of the cases no identifiable factor that caused the defect is not found, it is a common misbelief that congenital heart diseases are hereditary though few are so.
Congenital heart problems range from simple to complex. Some heart problems can be watched by the cardiologist and managed with medications, while others will require surgery, sometimes as soon as in the first few hours after birth. Some congenital defects heal spontaneously on medication, some require a single surgery, and more complex ones require multiple surgeries at various ages. Congenital heart defects can be classified into several categories according to the problems your child may experience. They include the following:
Problems that cause too much blood to pass through the lungs -- These defects allow oxygen-rich (red) blood that should be traveling to the body to re-circulate through the lungs, causing increased pressure and stress in the lungs. Examples include the following:
- patent ductus arteriosus (PDA)
- atrial septal defect (ASD)
- ventricular septal defect (VSD)
- atrioventricular canal (AV canal or AVC)
Problems that cause too little blood to pass through the lungs - These defects allow blood that has not been to the lungs to pick up oxygen to travel to the body. The body does not receive enough oxygen with these heart problems, and the baby will be cyanotic, or "blue." Examples include the following:
- tricuspid atresia (TA)
- pulmonary atresia (PA)
- transposition of the great arteries (TGA)
- tetralogy of Fallot (TOF)
Problems that cause too little blood to travel to the body -- These defects are a result of underdeveloped chambers of the heart or blockages in blood vessels. Examples include:
- coarctation of the aorta
- aortic stenosis
- pulmonary stenosis
A combination of several heart defects -- These combinations create a more complex problem that can fall into several of these categories. Complex combination of heart defects include:
- hypoplastic left heart syndrome (HLHS)
- truncus arteriosis
- total anomalous pulmonary venous return (TAPVR)
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The normal heart has two sides, the left and the right, which are separated by a muscular wall called the septum. Each side of the heart also has two parts -- an upper chamber called an atrium, and a lower chamber called a ventricle. Atrial septal defect (ASD), a congenital (present at birth) defect, occurs when there is an opening in the atrial septum, or dividing wall between the two upper chambers of the heart, known as the right and left atria.
Normally, oxygen-poor blood returns to the right atrium from the body, travels to the right ventricle, then is pumped into the lungs where it receives oxygen. Oxygen-rich blood returns to the left atrium from the lungs, passes into the left ventricle, then is pumped out to the body through the aorta.An atrial septal defect allows oxygen-rich blood to pass from the left atrium through the opening in the septum, and then mix with oxygen-poor blood in the right atrium.Treatment can be by 2 methods
Cardiac Catheterization or Device closure:
An umbrella shaped device is plced across the defect and enlarged to close it. This does not require any wound on the chest, it is done via blood vessels.
Those ASDs that cannot be closed by device are closed by surgery. This can be closed either through the front or from the side.
We have done several hundreds of this surgery during the last few years without any death or serious complications, cosmetic surgeries through thoracotomy are done for female children.
Ventricular septal defect (VSD), is an opening in the dividing wall between the two lower chambers of the heart known as the right and left ventricles.
A ventricular septal defect allows oxygen-rich blood to pass from the left ventricle through the opening in the septum, and then mix with oxygen-poor blood in the right ventricle.
Few VSDs can be closed by devices, a few are being done at our institute
Some types of VSDs will close on their own with time. Many, however, are too large or are positioned such that they cannot close on their own and require surgical closure.
Each year more than hundred VSD closures of varying complexity is being done in our unit without any mortality
3). Tetralogy of Fallot
Tetralogy of Fallot is a complex condition with multiple defects 1) VSD 2) Right ventricle outlet is partially obstructed with muscles 3) Right ventricular muscles are thickened 4) Aorta partially arises from the Right ventricle. This i\s the most common blue disorder.
With mild right ventricle obstruction, the pressure in the right ventricle can be slightly higher than the left. Some of the oxygen-poor blood in the right ventricle will pass through the VSD to the left ventricle, mix with the oxygen-rich blood there, and then flow into the aorta. The rest of the oxygen-poor blood will go its normal route to the lungs. These children may have slightly lower oxygen levels than usual, but may not appear blue.
With more serious obstruction in the right ventricle, it is harder for oxygen-poor blood to flow into the pulmonary artery, so more of it passes through the VSD into the left ventricle, mixing with oxygen-rich blood, and then moving out to the body. These children will have lower than normal oxygen levels in the bloodstream, and may appear blue.
Surgical correction is the only hope of cure and is typically carried out through an incision in the middle of the chest. The hole in the wall between the right and left ventricles, or VSD, is closed with a patch of Dacron cloth or a patch of thin leather-like material called pericardium. The muscle bundles and the narrowed pulmonary valve blocking the right ventricle are divided, and the passage out of the right ventricle toward the lungs is widened, usually by applying a patch to this area. Single stage total correction is being done at all ages with excellent results, more than a hundred cases are being done every year.
4). Total anomalous pulmonary venous connection (TAPVC)
When a fetus is developing, the pulmonary veins are a single channel which must establish a connection to the developing left atriumthe veins bringing pure blood from the lungs must connect to the left atrium. If it doesn't connect, other pathways for pulmonary venous drainage are created. The surgical repair is to connect the abnormal veins to the left atrium, many a times the child is cooled to very low temperatures and circulation is stopped.
5). Transposition of great arteries
In transposition of the great arteries, the aorta is connected to the right ventricle, and the pulmonary artery is connected to the left ventricle -- the exact opposite of a normal heart's anatomy.
returns to the right atrium from the body, passes through the right atrium and ventricle, then goes into the misconnected aorta back to the body.
returns to the left atrium from the lungs, passes through the left atrium and ventricle, then goes into the pulmonary artery and back to the lungs.
Within the first 1 to 2 weeks of age, transposition of the great arteries is surgically repaired. The procedure that accomplishes this is called a "switch," which roughly describes the surgical process. The aorta and pulmonary arteries are disconnected and reconnected to their proper ventricles. The coronary arteries must be transferred to the newly positioned aorta as well, or "blue" blood will supply the muscle of the heart. Associated holes between the chambers of the heart are closed. The heart is then restarted as the heart-lung machine is withdrawn.
Aterial switch with comlpex anatomy of coronaries are being done, a newborn weighing 1.7kgs was the smallest child treated succesfully.
6). Tricuspid atresia
In tricuspid atresia, the following occurs:
Improper development of the tricuspid valve
prevents oxygen-poor blood from passing from the right atrium to the right ventricle and on to the lungs as it should.
The right ventricle is underdeveloped.
Openings are present in the atrial and ventricular walls
, allowing oxygen-poor blood and oxygen-rich blood to mix.
Surgical Repair -- A series of operations are performed in the first two years of life that will re-route blood so that enough oxygen is added to the bloodstream to meet the child's needs. Types of operations include the following:
1). Modified Blalock-Taussig Shunt - A synthetic graft is placed in from an artery to the blood vessel suppying the lung, this increases the blood supply to the lungs, so that the child is less cyanotic. This is usually done in the new born period.
2). Glenn Shunt -- A second operation, often performed at about 4 to 12 months of age, this replaces the Blalock-Taussig shunt and the superior vena cava (the large vein that brings oxygen-poor blood from the head and arms back to the heart) is connected to the right pulmonary artery. Blood from the head and arms passively flows into the pulmonary artery and proceeds to the lungs to receive oxygen. Oxygen-poor blood returning to the heart from the lower body through the inferior vena cava will still mix with oxygen-rich blood in the left heart and travel to the body, so the child will remain mildly cyanotic.
3). Fontan Procedure -- The Fontan procedure is for treatment of children with single ventricle. The basic principle of the Fontan operation is that it is not necessary to have a ventricle to pump to the lungs as long as the lung arteries have a low resistance, are well developed and are of a good size, and as long as the single ventricle fills at a low pressure. The surgery involves a direct connection of the blue blood returning from the lower half of the body to the heart into the pulmonary arteries.
7). Atrioventricular Canal
Atrioventricular canal (AV canal or AVC) defect is a complex congenital defect that results in a large hole in the center of the heart. This defect involves several abnormalities of structures inside the heart:
An atrial septal defect
allows oxygen-rich blood to pass from the left atrium through the opening in the septum, and then mix with oxygen-poor blood in the right atrium.
A ventricular septal defect
allows oxygen-rich blood to pass from the left ventricle through the opening in the septum, and then mix with oxygen-poor blood in the right ventricle.
Abnormalities of the mitral or tricuspid valves
allow blood that should be moving forward from the ventricle into either the pulmonary artery or the aorta to instead flow backward into the atria.
Surgical repair is the only option, it is a complex repair involving repair of valves and closure of VSD and ASD.
The cost of surgery depends on the type of surgery performed and the economic category to which the patient belongs. The institute offers subsidised treatment to patients from lower socio economic status. All patients belonging to subsidised categories under 18 years of age from the state of Kerala can avail “THALOLAM” scheme, by the Goverment of Kerala for free treatment (up to Rs 50000/-,currently) in this hospital. The amount stated for surgery is a package, the final cost may vary, in case of additional procedures or if recovery is prolonged.
We are one of the only two institutions in the public sector in India, dealing with surgical correction of complex congenital heart disease. Regrettably, we have a long waiting list. Moreover, we often have do surgeries, mostly in newborns, in an emergency basis, which often delays the elective surgeries. We have started a new prioritisation system based on the urgency of each case. After evaluation in our OPD, patients are triaged into urgent, early and elective groups and a priority number is given .The patients are informed over phone or via letter as to when they should report for surgery. At times we are not able to adhere to the dates promised to these patients due to unforeseen difficulties, but we do as best as we can to make both ends meet.
Some of the congenital diseases like TAPVC, coarcatation of Aorta etc need to be operated at once even at times in a day or two after birth. In some conditions surgery as be postponed for while allowing the child to grow up a bit, but earlier surgery sets the blood circulation right at an younger age ,allowing critical organs like brain to develop properly.
Pediatric cardiac surgery is around 60 years old and some surgeries performed now were started in 1970s , the long term results are being seen now. Many of the simple conditions like ASD,VSD,PDA etc can be considered completely cured once operated upon. Other complex conditions like Tetralogy, Transposition , Single ventricle etc surgery provides a great relief to the patient and help them to lead a normal life in most cases but some may have varying degrees of disabilty and higher chance of premature death. This depends on the type of disease and the completeness of the procedure performed.
Almost all children will be able to attend school after surgery, and some of them do well in studies and sports. Some of them have become dancers even. Studies inlvolving children who have undergone major cardiac surgery involving cooling of the brain and circulatory arrest have shown that they may develop minor changes in level of cognitive performance.
After corrective surgery, when the child is completely cured, graded activity can be started few weeks after surgery and full activity after six months. For those who have undergone palliative surgery they may develop fatigue early. Generally heavy physical activity should be avoided for six months after surgery.
General care:The child can be given daily bath with soap and warm water. Too many visitors and a too much travel should be avoided. During recovery phase children need nutritious food hence they must be given a balanced diet.
Wound: Should be inspected daily for any increased pain, redness or fluid discharge, if any change is seen , it should be shown to a local surgeon or if possible should be shown in the OPD
Urine output: If there is a decrease in urine output or if the child is looking puffy then they should be shown to a local cardiologist or shown in the OPD
Diarrhoea or decreased appetite can lead to dehydration which may lead to block of shunts placed to supply blood to the lungs, this may be manifested by increased bluish discoloration, this is an emergency they should get specialised care immediately.
Minor illness may be shown to a local physician , but if symptoms like prolonged fever,weight loss or abdominal pain persists they should undergo an evaluation with a specialist cardiologist and if needed the child can be brought to the OPD. Any of our doctors in the pediatric division may be contacted if there is an emergency so that we can communicate with the cardiologist taking care of the patient.
Some children who present with cardiac failure may require salt and fluid restriction, this will be given in the instructions at the time of discharge. Generally no diet restriction is needed in most patients after surgery.
Most children may require medications for 3-6 months after surgery which is usually discontinued after the first review. Some require lifelong medications this depends on the type of surgery performed.