Congenital Heart Disease
Congenital heart disease or a hole in the baby’s heart is one of the most common congenital (present since birth) anomaly and occurs in 9 of every 1,000 babies born. This is a structural problem which occurs during the development of the baby’s heart when the baby is in the mother’s womb. Development of the baby’s heart starts after conception and is nearly complete by 8 weeks of gestation. A series of specific steps should occur for normal development of the heart, one of the steps not happening at the right time results in development of congenital heart disease. For E.g. Incomplete formation of a dividing wall leaving behind a hole in between two chambers of the heart or narrowing of one of the valves of the heart resulting in decreased flow to the body.
Normally human heart has four chambers. Two receiving chambers also call atria and two pumping chambers also call ventricles. Vessels which bring blood to the heart are call veins and vessels which take away blood from the heart are called arteries. Impure blood (blood with low oxygen and high carbon dioxide) is brought to the right sided receiving chamber (Right atrium) from upper and lower part of the body via superior and inferior venacava respectively. This blood is then pumped to the right and left lung via the pulmonary artery by the right sided ventricle. This blood undergoes purification in the lung (Oxygen is added and carbon dioxide is removed) and transported to the left sided receiving chamber (left atrium) via 4 pulmonary veins (2 each from right and left lung). This blood is then pumped by the left sided ventricle to the entire body through the main artery of the body (Aorta). Normally the pressure in the left sided chambers is three times that of the right sided chanbers. Normal pressure in the right atrium is around 3 mm Hg (range 2-8 mm Hg), in the right ventricle systolic pressure is 15-20 mm Hg and diastolic pressure is 0-8 mm Hg. Mean pulmonary artery pressure is 12-19 mm Hg, Left atrial pressure is usually 8 mm Hg (6-12 mm Hg). Right side of the heart is usually weaker as compared to the left side of the heart as it has to pump blood only to the lungs and that too at a much lower pressure.
Parents are often apprehensive about will if something they did during the pregnancy caused the heart problem. Although some of the congenital heart diseases are genetic in origin or can occur due to some medications (like anti-seizure or antiacne medications or even alcohol and substance abuse) taken by the mother during pregnancy, in most cases, no specific cause can be found.
Heart disease could be classified into three different types:
Holes in various positions of the heart allow oxygen-rich blood that should be traveling to the body to recirculate through the lungs. This results in increased flow as well as pressure in the lung arteries. These babies usually have symptoms of heart failure like difficulty in feeding and breathing, recurrent cough and cold and poor weight gain. Some of these are
Holes in the between the lower chamber of the heart along with narrowing of the lung arteries results in less amount of blood to pass through the lungs. Thus impure blood (low oxygen and high carbon dioxide) recirculates in the body vessels. The babies with this heart disease have bluish discolouration of their lips and finger nails. They may have “cyanotic spells”. These spells usually occur just after baby gets up from sleep or after trying to pass stools, the baby becomes irritable, breathes fast, has inconsolable cry with increase in bluish discolouration. Unlike the babies with too much blood flow, these babies are usually well grown and do not have feeding or breathing difficulties.Some of these are
Blockages in the main artery of the body, underdeveloped chambers or narrow valves of the heart could prevent proper amount of blood from traveling to the body. More often than not these babies are very sick and require surgery very early after birth. Some of these are
Some cases could have a mixture of several heart defects creating a more complex problem. Some of these are
Most of these congenital heart disease can be diagnosed in the mothers womb by doing a specialised test called the Fetal Echocardiogram.
Considering a birth prevalence of congenital heart disease as 9/1000, the estimated number of children born with congenital heart disease in India is more than 200,000 per year. Of these, about 40,000 (20%) are likely to be critical requiring intervention in the first year of life. Currently advanced cardiac care is available to only a minority of such children. Although, a number of cardiac centres have been developed in India over the last 10 years, most of them are in private or corporate hospitals concentrated in metro cities like, Mumbai, Delhi, Bangalore, Hyderabad, Kolkata and Chennai. Challenges to paediatric cardiac care include financial constraints, health-seeking behaviour of community, and lack of awareness. Government of India is taking a number of steps for improving health of children through its various program and schemes that are likely to benefit children with congenital heart disease, especially those who are vulnerable and marginalized.
Babies with congenital heart defect require meticulous diagnosis, surgery and post-operative care. This is usually done by a team of doctors consisting of a paediatric cardiologist, paediatric cardiac surgeon, paediatric cardiac anaesthetist and paediatric cardiac intensive care specialist.
A paediatric cardiologist diagnoses the heart disease and help manage them before and after surgery, he also can treat certain congenital heart diseases with minimal invasive procedures like the device closure of various holes or balloon dilatation of narrow arteries and valves. In the western world, a new subspecialty within cardiology is emerging who care for adults with congenital heart disease. In some countries the ratio of adults with congenital heart disease is even greater than the number of babies born with CHD. A similar trend has now started emerging in India as well. This improved survival is a result of advances in diagnostic procedures and treatment interventions. Other subspecialities in paediatric cardiologist are
- Pulmonary hypertension specialist
- Heart failure specialist
- Fetal cardiologist
- Paediatric cardiac intervention specialist.
The surgery by itself is done by the paediatric cardiac surgeon with assistance from paediatric cardiac anaesthetist (doctor who puts the baby to sleep) and paediatric cardiac intensive care specialist (manages the baby in the ICU after surgery).
Babies with congenital heart defect require meticulous diagnosis, surgery and post-operative care. This is usually done by a team of doctors consisting of a paediatric cardiologist, paediatric cardiac surgeon, paediatric cardiac anaesthetist and paediatric cardiac intensive care specialist.
Ideal time for intervention in patients with congenital heart disease will vary according to the type of the heart disease as well as the clinical presentation of an individual patient. In some heart diseases the intervention might be required immediately after birth while in others the intervention can be done even in adult life. The approximate time lines for interventions in some common heart diseases are as follows. CHD requiring intervention within few hours or days after birth:
Transposition of great arteries
- Total anomalous pulmonary venous drainage
- Hypoplastic left or hypoplastic right heart syndrome
- Coarctation of aorta or interrupted aortic arch
- Critical aortic or pulmonary stenosis
- VSD with pulmonary atresia
CHD requiring intervention in the first year of life
- Large VSD, PDA, AP window
- Truncus arteriosus
- Tetralogy of Fallot
- Atrioventricular septal defect
- Double outlet right ventricle
- Single ventricular surgeries (Bidirectional Glenn shunt)
- Aortic or pulmonary stenosis
CHD requiring intervention in the first decade of life
Almost 20% of the congenital heart diseases are critical which require surgery to be done within the first few months or even days of life. If not treated most of these children would succumb to infections or heart failure. Those that survive infancy often are frail with poor weight and limited in functional capacity.
Yes, Most of the children with congenital heart disease if treated in time could lead a near normal life. Very few children require multiple surgeries or have to be on lifelong medications.
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