Congenital Heart Defects

What is congenital heart disease?

Congenital heart disease is a heart condition you are born with. The word congenital means “present at birth.” Congenital heart disease can range from very minor conditions which never cause problems, to more serious conditions that require treatment.

A congenital heart defect happens when the chambers, walls or valves of your heart – or the blood vessels near the heart – don’t develop normally before birth. There are many different types of defects listed below.

1. Holes in the heart (septal defects)

When a baby is born with an abnormal opening in the wall that separates the right and left chambers of the heart (the septum), blood can leak between the chambers instead of flowing normally to the rest of the body. This may cause the heart to become enlarged.

The most common holes in the heart are:

• Atrial septal defect (ASD) Normally, oxygen-rich blood that’s already been to the lungs flows from the left atrium to the left ventricle, out the aorta and to the body. An abnormal opening between the right and left atria (the upper chambers of the heart) allows some blood from the left atrium to leak back into the right atrium. Your heart has to work extra hard to move the extra blood out to the lungs. The seriousness of the problem depends on the size of the opening.

  Patent foramen ovale (PFO) is one type of atrial septal defect. The hole between the left and right atria usually closes within the first few years of life. Even if it doesn’t close, the hole may not cause any complications unless you have a second heart defect. PFOs are very common and many people will never know they have one.

• Ventricular septal defect (VSD) If there is a hole between your right and left ventricles, oxygen-rich blood returning from your lungs leaks from the left ventricle into the right ventricle instead of being pumped into the aorta and out to the rest of your body. Depending on the size of the opening, you may need surgery to close the hole.

2. Obstruction of blood flow

Stenosis is a narrowing or obstruction in heart valves, arteries or veins that affects the flow of blood. Atresia is when a passageway in the body is abnormally shut or has not formed properly. Different types of stenosis and atresia can partly or completely block blood flow in the heart.

• Pulmonary valve stenosis If your pulmonary valve narrows, the flow of oxygen-poor blood from the right ventricle through the pulmonary arteries to your lungs is restricted. This interferes with the blood’s ability to pick up oxygen and deliver it to the rest of your body. The right ventricle has to work harder to pump blood through the narrowed pulmonary valve and the pressure in the heart is often increased.
• Pulmonary atresia The pulmonary valve lets blood flow from the right ventricle to the lungs via the pulmonary artery. In pulmonary atresia, the pulmonary valve does not form properly and it remains closed at birth. Blood is not able to flow properly to the lungs to get oxygenated. If left untreated, this condition is fatal. Visit About Kid’s Health to learn more.
• Tricuspid atresia The tricuspid valve controls blood flow between the right atrium and the right ventricle. In tricuspid atresia, the valve does not form properly and there is no opening between these two chambers. Blood is not able to flow from the right atrium into the right ventricle and then onto the lungs, to get oxygenated. If left untreated, this condition is fatal. Visit About Kid’s Health to learn more.
• Aortic stenosis When the aortic valve narrows, blood flow is restricted from the heart through the main artery to your body (aorta) and onwards to the rest of the body. As a result, the left ventricle has to contract harder to push blood across the aortic valve. This eventually weakens the heart muscle and makes your heart less efficient. Surgery may be necessary. Aortic stenosis can be treated, but life-long follow-up will be needed.
• Coarctation of the aorta This is the narrowing of the largest artery in the body. When the aorta is pinched or constricted, the flow of blood to the lower part of the body is reduced and blood pressure above the constriction is increased. The heart is forced to pump harder in order to deliver enough blood to the rest of your body. Coarctation of the aorta can range from mild to severe. It usually occurs with other heart defects. The condition can be treated, but life-long follow-up will be needed.
• Patent ductus arteriosus The ductus arteriosus is a passageway for blood between the aorta and pulmonary artery that normally closes a few days after birth. If it fails to close properly, too much blood flows to the lungs. The condition is common in premature babies, but rare in full-term babies. How serious it is depends on how large the opening is and how premature the baby is. In some circumstances an open ductus is necessary for survival – where blood flow is blocked, or if the blood vessels supplying the lungs and body are switched (transposition of the great arteries).

  Medication in the first few weeks of life can either close (or keep open) the ductus arteriosus. As your baby gets older and if the medication isn’t working, the ductus can be closed off using a cardiac catheterization procedure. This will restore normal circulation.

• Blue babies (cyanotic defects) When blood that is pumped from the lungs and heart to the body contains less-than-normal amounts of oxygen, it causes a blue discoloration of the skin, lips, gums, nail beds, and the areas around the eyes and mouth (cyanosis). There are several different conditions that can lead to a blue baby.
  • Tetralogy of fallot is a combination of four defects that make the level of oxygen in the blood too low:
    • A large hole in the wall between the two ventricles allows some oxygen-rich blood to be pumped to the right side of the heart instead of to the rest of the body through the aorta. (See ventricular septal defect above.)
    • A narrowing of the pulmonary valve can block the flow of blood from the right side of the heart to the lungs. (See pulmonary valve stenosis above.)
    • A more-muscular-than-normal right ventricle can cause the heart muscle to become stiff over time, eventually making the heart weak (right ventricular hypertrophy).
    • An aorta that lies directly over the right ventricle allows a mixture of oxygen-rich and oxygen-poor blood to flow into the aorta (overriding aorta).
  • Transposition of the great arteries In this condition, your baby’s pulmonary artery and the aorta are reversed. Their aorta is connected to the right ventricle, so most of the blood returning to the heart from the body is pumped back out to their body without first getting oxygen from the lungs. The pulmonary artery is connected to the left ventricle, so that most of the oxygen-rich blood returning from their lungs goes back to the lungs again. The condition is often detected during the first week of life and can be corrected with surgery during your baby’s first month.

    Other defects between the right and left sides of the heart often co-exist with transposition of the great arteries. An atrial septal defect, ventricular septal defect or ductus arteriosus can actually help oxygenated blood circulate to the body.

  • Ebstein’s anomaly The tricuspid valve controls blood flow between the right atrium and the right ventricle. Ebstein’s anomaly is a rare condition in which the tricuspid valve is located lower than normal and has abnormal flaps (leaflets). This can cause blood to leak backwards through the valve and prevent the heart from working efficiently. This causes the ventricle to be too small and the atrium to be too large. Many children with Ebstein’s anomaly have mild cases that don’t cause symptoms. If your child’s tricuspid valve is leaking badly, heart valve surgery may be necessary.
• Hypoplastic left heart syndrome Children born with this syndrome have an underdeveloped left side of their heart.
  • The left ventricle is underdeveloped and too small.
  • The mitral valve is not formed or too small.
  • The aortic valve is not formed or too small.
  • A part of the aorta (the ascending aorta) is underdeveloped or too small.

  Children with this condition often have an atrial septal defect as well (see above).

• Information taken from https://www.heartandstroke.ca/heart/conditions/congenital-heart-disease