Congenital Heart Defect

What is a Congenital Heart Defect?

A congenital heart defect is a problem with the structure of heart and the great vessel and is present at birth.  It is one of the most common types of major birth defect.

The defect can occur in the structure of the heartbecause of incomplete or abnormal development. It can be anywhere such as on the wall of the heart, on the valves of the heart or arteries or veins which are near the heart which change the normal flow of blood through the heart or the blood can flow in the wrong place or in the wrong direction.

Many of these defects are simple condition which sometime even don’t need any treatment and if needed can be easily fixed. But there are also complex heart defects which need which requires special medical care soon after the birth. But fortunately the diagnosis and treatment of complex congenital heart defects has greatly improved in present era. Hence all children who have complex heart defects can be treated and they can survive to productive adulthood.
Congenital heart defect is also known as congenital heart disease, congenital cardiovascular malformations and heart defects.

Types of Congenital Heart Defects

There are over 30 different types of congenital heart defects. However they have been categorized into 3 categories such as:

Septal Defects: When there is a hole in the septum (wall that separates the chamber on right and left sides of the heart) of heart, which allows blood to mix between the two sides of the heart is known as septaldefects. These defects are commonly known as “hole in the heart”.  

Obstruction Defects: When one of the valves or ventricles is narrowed to such a degree that it partially or completely blocks the flow of blood is known as obstructive defects.

Cyanotic Heart Disease: When there is more than one hole within the heart which leads to a lack of oxygen being pumped around the body is known as cyanotic heart disease.

Some Examples of Congenital Heart Defects

Atrial SeptalDefect (ASD)

In ASD there is a hole in the septum which separates the upper chambers (atria) of the heart. This hole causes oxygen-rich blood to flow into the right atrium from left atrium, instead to flow into left ventricles. ASDs can be of any size. The smaller the hole the less blood is to leak from one atrium to another and bigger the hole more blood flow from one atrium to another.

Many small holes may be harmless and allow heart to function as it should and don’t need any special treatment and even sometime these small holes may close on their own as heart grows during childhood. However bigger holes are unlikely to close on their own and need to be treated.

Ventricular Septal Defect(VSD)

In VSD there is a hole in the septum which separates the lower chambers (ventricles) of the heart. This hole causes oxygen-rich blood to flow into the right ventricle from the left ventricle, instead to flow into the aorta and then out to the rest of the body. VSDs can be of any size. The smaller the hole the less blood is to leak from one ventricle to another and bigger the hole more blood flow from one ventricle to another. This condition will make heart to work harder than normal and also the extra blood flow increases the blood pressure in the right side of the heart and the lungs which can lead to heart failure.

Many small holes usually don’t cause any harm and may close on their own. However larger holes are unlikely to close on their own and need to be treated.

Patent DuctusArteriosus (PDA)

In PDA abnormal blood flows occur between the aorta and pulmonary artery because ductusarterious doesn’t close.

DuctusArterious: It is a short broad vessel in the fetus that connects the pulmonary artery with the aorta and conducts most of the blood directly from the right ventricle to the aorta bypassing the lungs.

Soon when the infant is born and the lungs filled with air the ductusarterious is no longer needed so within minutes or up to a few days after birth, it closes.

However in some babies this ductusarterious doesn’t close allowing oxygen-rich blood from the aorta to mix with oxygen-poor blood from pulmonary artery. This can strain the heart and increase blood pressure in the lung arteries.

Small PDAs often close without treatment but others need treatment. Because at beginning the symptoms of PDAs might be only heart murmur, but in the first year of life include increased work of breathing and poor weight gain. If it is not treated, these may lead to congestive heart failure.

Tetralogy of Fallot

In tetralogy of fallot there is a combination of four heart defects that are present at birth. These defects will affect the structure of the heart andcan cause oxygen-poor blood to flow out of the heart and into the rest of the body. Those four combinations of defects are:

• Pulmonary valve stenosis.
• A large VSD.
• An overriding aorta. In this defect, the aorta is located between the left and right ventricles, directly over the VSD. As a result, oxygen-poor blood from the right ventricle can flow directly into the aorta instead of into the pulmonary artery.
• Right ventricular hypertrophy(hi-PER-tro-fe). In this defect, the muscle of the right ventricle is thicker than usual because it has to work harder than normal.

Due to circulation of oxygen-poor blood the babies can have cyanosis and can be very severe.

Pulmonary Valve Stenosis

The most common valve defect is the most common valve defect. Pulmonary valve stenosis is a heart valve disorder that involves the pulmonary valve.

Pulmonary valve stenosis can be mild ones as well as severe one. If the stenosis is mild one then the treatment is not needed but severe stenosis need treatment.

Some babies can have valve stenosis with PDA or ASDs in which oxygen-poor blood will flow from the right side of the heart to the left side. Due to low level of oxygen in the blood coming out of heart the skin, lips and fingernails of the baby tinged to bluish or purplish. This is called cyanosis.

Atrioventricular Canal Defect

Atrioventricular canal defect is also known as atrioventricularseptal defect. In this defect the central area of the heart is poorly formed or simply described as a large hole in the middle of the heart.  This hole occurs due to a lack of separation of the atria and the ventricles into separate chambers. Also due to a lack of separation of the mitral and tricuspid valves into two separate valves.Instead of two separate valves, tricuspid on the right and mitral valve on the left which allows blood flow into the heart, one large common valve is formed. There are even more complex forms of these defects where ventricles may be not formed properly or valves may be an obstruction to aorta.

Due to these septal defects a large amount of blood excess amount of blood goes to lungs cause blood pressure to rise which can damage the blood vessels.  Also the upper and lower chambers may not close properly causing blood to leak back. As a result heart will work harder to pump more blood which can cause the enlargement of heart.

Atrioventricular canal defect is commonly seen in children with Down syndrome.

Causes of Congenital Heart Defects

The cause of most congenital heart defects is unknown. Whereas it is believed that heredity may play a role in some congenital heart defects for example parents with this defect are more likely to have a child with the defect. However it is rare case to have more than one child in the family to born with heart defects.

Congenital heart defects are associated with genetic disorders, such as Down syndrome. In fact, half of all babies who have Down syndrome have congenital heart defects.

Also during pregnancy if the mother is having certain infection such as rubella or poorly controlled diabetes or smoking during pregnancy has been linked to several congenital heart defects.

Development of Congenital Heart Defects

The third week (22 days) after conception of the baby, heart began to develop. The heart at that time has a simple tube shape and within 22-24 days the heart bends toward right and begin to form a looping structure, distinct chamber begin to appear. As looping proceeds after 28 days the tube has a vaguely heart-like shape with structures corresponding to the heart’s two sides and the large blood vesselsthat carry blood in and out of them. But heart is completely formed by eight weeks (56 days)after conception.

During this crucial first eight weeks of baby’ development the defect can occur in the structure of the heart because of important steps not happening at the right time or the structure  becomes incomplete or abnormally development.

The Rise of Congenital Heart DefectsInAdulthood

Even though congenital heart defects are treated in the childhood, only in seldom cases it been completely cured, but in most cases they are been repaired to improve the heart function.  This is the cause people who had been treated for this defect should be getting a follow up checkup.

Many treatments which been used to repair heart defects may leave scar tissues in the heart with can cause arrhythmia in adulthood. Also the treatment might have worsen and need further treatment. Elsewhere it can rise complications or even cause greater risk of other heart problems.

Symptoms of Congenital Heart Defects

Many congenital heart defects don’t have any signs and symptoms and if exist then very few. Sometime it’s even difficult for medical personals to detect the defects in a regular physical examination.

A congenital heart defect doesn’t cause any chest pain or any other painful symptoms.  It can cause heart murmur but heart murmur is not only the sing of congenital heart defect.

Symptoms of Severe Congenital Heart Defects

Severe congenital heart defects usually become evident very fast. It can be as fast as within few hours or it can be visible within few months of life. The signs and symptoms may include:

• Loss of healthy skin color
• Rapid breathing
• Cyanosis (a bluish tint to the skin, lips, and fingernails)
• Shortness of breath during feedings or get tired while feeding
• Poorweight gain
• Swelling in the leg, abdomen or areas around eyes

Symptoms of Less-Severe Congenital Heart Defects

There are some congenital heart defects which are not diagnosed until later in childhood which may be less severs ones.  The signs and symptoms of these less severscongenital heart defects may include:

• Shortness of breath during simple exercise
• Fatigue (tiredness) during physical activity
• Swelling in the hands, ankles or feet
• Fluid buildup in lungs

Symptoms of Congenital Heart Defects in Adult

After many years of treatment the signs and symptoms of congenital heart defects may rise. The signs and symptoms of some typicalcongenital heart defects in adult may include:

• Arrhythmias (Abnormal heart rhythms)
• Cyanosis (A bluish tint to the skin)
• Shortness of breath
• Becoming fatigue (tired) very quickly upon exertion
• Dizziness or fainting
• Edema (Swelling of body tissue or organs)

What are the risk factors of Congenital Heart Defects?

Cause of many congenital heart defects is unknown. Here are some risk factors which may cause heart defects.

Viral Infection:Rubella is a disease caused by the rubella virus and is one of the risk factor. It is also commonly known as German measles. Women who contract rubella during the first three months of pregnancy have an increased risk of having a baby with a heart defect. If a woman is not vaccinated against the virus then it is advised to talk with doctor. Also women should avoid becoming pregnant for one month after receiving the MMR vaccine.

Diabetes:Research has suggested that women with diabetes are five times more likely to have a child with heart defects than normal women.Having this chronic condition may interfere with the development of the baby’s heart. Hence those mothers with diabetes need to ensure that the condition is under controlled throughout their pregnancy.

Heredity:Congenital heart defects appear to run in families and are associated with many genetic syndromes.Half of all babies who have Down syndrome have congenital heart defects. About 1 in 4,000 babies is born with deletions (a missing piece) in a specific region of chromosome 22 which causes a variety of problems that can include heart defects.

Medications: Certain medicines during pregnancy can cause birth defects that can include heart defects. Hence it is advised that during pregnancy consult with doctors. Medications include lithium (used to manage bipolor disorder), Accutane (acne medication) and, possibly, some anti-seizure medications can increase the risk.

AlcoholConsumption of alcohol during pregnancy may cause heart defects. Babies born with fetal alcohol syndrome (FAS) often have problems with their heart.