Hole in the heart is a layperson's term to describe a congenital abnormality of the heart - congenital meaning present at the time of birth.
The term is used to describe an actual hole in the walls separating the heart chambers, or as a general term to describe a structural abnormality of the heart.
The heart is the central blood pumping station of the body. It is constructed like a house with four rooms. The top two rooms are called atrium and the bottom two rooms are called ventricles. The wall which separates the top two rooms is called the atrial septum and the wall which separates the bottom two rooms is called the ventricular septum.
Therefore a hole in wall between the top rooms is called an
atrial septal defect (ASD) and a hole in the wall between the bottom two rooms is called a
ventricular septal defect (VSD).
The blood which is low in oxygen, or blue blood, returns to the right sided rooms where it is passed from the top room to the bottom room and to the lungs. In the lungs, the blood receives oxygen. This blood with the increased oxygen content, or pink blood, returns to the left top and bottom rooms and then to the body.
Inlet valves separate the top and bottom rooms of the heart. An outlet valve allows blood to be pumped from the right lower room to the lungs. This is called the pulmonary valve. The outlet door which allows blood to pump from the left lower room is called the aortic valve.
Hence the "heart house" has four rooms and four doors and two separating walls. Blue blood is pumped through the right heart to the lungs and the pink blood is pumped through the left heart to the body. The term hole in the heart may encompass not only holes between separating walls but also includes abnormal connection between the rooms, and abnormality of the doors and blood vessels.
This is estimated to be about 8 per 1,000 live births. If we have 50,000 live births a year, then we expect about 400 children a year with congenital heart defects.
The most common is ventricular septal defect i.e. a hole in wall between the bottom two rooms. This forms about 30% of all congenital heart defects. The other defects in the range of 6% to 10% include atrial septal defect (hole in wall between the top two rooms), pulmonary valve stenosis (narrowing of the right outlet door), aortic valve stenosis (narrowing of the left outlet door) and patent ductus arteriosus (persistence of a communication between the two major blood vessels of the heart).
This group of heart conditions belong to the "pink" hearts i.e. the blood travelling out from the heart to the body is fully oxygenated.
About a quarter of congenital heart defects are what we call "blue" hearts or cyanotic hearts. Here, the defect of the heart allows the right heart blood which has low oxygen content, or "blue" blood, to mix with the left heart blood which has high oxygen content, or "pink" blood.
The most common of the "blue" heart is called Fallot's tetralogy, named after a French doctor who described the condition. Here, the combination of hole in the heart, narrowing of the vessel to the lungs and overriding of the blood vessel to the body across the hole results in the "blue" blood mixing with the "pink" blood. Hence the child appears "blue". This is visible on the finger tips and lips.
The majority of patients with heart defects have no symptoms and do not require treatment. It is estimated that about 25% of infants presenting in infancy require medical treatment or surgery.
Singapore has a very effective screening health programme. Soon after birth, all babies are screened by doctors for congenital abnormalities. This includes heart defects.
Some significant defects are symptomatic soon after birth i.e. baby may be breathless, blue or not feeding well.
More commonly, babies have no symptoms. But the physician, on listening to the heart with his stethoscope, hears an additional heart sound called a heart murmur. Ninety-five per cent of the time, the heart murmur arises from the sound of blood flowing in a normal heart.
If there is suspicion of a structural heart defect, the baby is referred to the paediatric cardiologist for evaluation.
Yes, that is possible because some remain asymptomatic, while others have murmurs which become more obvious after 3 to 6 weeks of life.
But because most infants are reviewed by doctors for immunisation and developmental assessment in the first year of life, significant congenital heart defects are rarely left undiagnosed in Singapore. By the time they are in school, the majority of patients picked up by the school health team for heart murmurs have structurally normal hearts.
The paediatric cardiologist can often tell by examination whether a heart murmur is significant. The simple tests include a chest X-ray and an electrocardiogram. The chest X-ray is used to tell the shape and size of the heart and the state of the lungs. An electrocardiogram analyses the electrical activity of the heart. If the clinical electrocardiogram and simple investigation is normal, we stop at that and reassure the parents.
If there is suspicion, an electrocardiogram is ordered. This is an ultrasound examination of the heart, like what the obstetrician will perform to look at the fetus in pregnant women.
Yes and no. The heart is formed by the eighth week of pregnancy. Antenatal ultrasound can be used to look at the heart at about 12 weeks onwards to look for heart defects. The majority of heart defects picked up antenatally are major and often serious abnormalities of the heart. Minor defects like small holes and mild valve defects, for example, will slip through this screening process.
The defect has to be carefully characterised and the type of treatment that is available and the long term outcome of treatment will have to be discussed with the parents. Depending on the type of defect, the stage of pregnancy, the philosophy of parents, their religious beliefs and family support, a decision is made to carry on to term or to terminate the pregnancy.
Not all heart defects need specific treatment. For example, if the child has a small hole in the heart such as a ventricular septal defect, no treatment is necessary. The child should be treated like any normal child and allowed normal physical activities. Most of these holes become smaller with time and some may close spontaneously. There is a small risk of bacterial infection of the area around the hole because of flow turbulence. Patients are advised to have good dental care, and if they were to undergo dental or surgical procedures, to take a prophylactic course of antibiotics to prevent bacteria from seeping into the blood and infecting the heart.
For significant defects, for example a moderate to large ventricular septal defect, the baby can present with heart failure - the signs of which include poor feeding, breathlessness and poor weight gain. We treat these babies with medication. Some improve as the defect becomes smaller over time. Others who do not improve with medical treatment are referred to the heart surgeon to close the defect surgically.
The majority of patients who undergo surgery for ventricular septal defects are babies in the first year of life. The child usually goes home from the hospital within 10 to 12 days.
Small ventricular septal defects have a good chance of closing spontaneously. The closure rate is estimated to be in the range of 30% to 50% and occurs most frequently in the first year of life.
Most adults with small or minor defects have no symptoms and lead a perfectly normal life. Some are detected because the doctor detected a heart murmur on routine examination. While others may have complications of significant defects like breathlessness on physical exertions.
This would depend on type and severity of the defect. If the defect is significant and surgery is deemed to improve the quality of life, surgery will be offered to these patients.
The complications that arise depend on the type of defect, site of defect in relation to vital heart structures and size of fetus. Let's talk about the ventricular septal defect as an example. A large defect can result in heart failure with failure to gain weight, recurrent respiratory infections and damage to the blood vessels in the lungs. A defect near the left outlet valve can result in damage to the valve and subsequent valve leakage. As mentioned before there is also risk of infection of the heart.
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