Is your baby's left side of the heart weak? Let's talk about Hypoplastic Left Heart Syndrome (HLHS)

It's hard to describe the feeling you feel when your doctor tells you that your newborn baby has a serious heart condition. Along with the fear, shock, and sadness, the question "What will happen to our baby?" echoes in your mind. It's a very difficult time. But the most important thing at a time like this is to be fully aware of this condition. Today we are going to talk about Hypoplastic Left Heart Syndrome (HLHS), a serious and rare heart condition that is caused by birth. In this article, we will talk about this simply, in a way that you can understand.

What exactly is Hypoplastic Left Heart Syndrome (HLHS)?

Simply put, Hypoplastic Left Heart Syndrome (HLHS) is a condition that occurs when the left side of the heart does not develop properly while the baby is growing in the womb. This is a congenital heart disease. The word "hypoplastic" means "underdeveloped."

Our heart is like a small house with four rooms. Two rooms upstairs and two rooms downstairs. The parts of the left side of the heart of a baby with HLHS, specifically:

• Left ventricle: This is the main pumping chamber of the heart. It pumps clean, oxygenated blood to the entire body. In HLHS, it is very small and underdeveloped.
• Aorta: The main blood vessel that carries blood from the left ventricle to the rest of the body. This is also often narrow and small.
• Mitral and aortic valves: These are like doors. They allow blood to flow in only one direction. In HLHS, these valves may not develop properly or may be completely closed.

Because these major parts don't grow properly, the left side of the heart can't pump enough oxygenated blood to the rest of the body. This is a very serious condition. Sometimes, there can be a small hole in the wall between the two upper chambers of the heart, called an atrial septal defect .

What is the difference between this and a healthy heart?

In a healthy heart, both the right and left sides work together. Imagine that the right side takes the oxygen-poor blood from the body and sends it to the lungs to get oxygen. The oxygen-rich blood from the lungs returns to the left side of the heart. Then the powerful pump on the left side (the left ventricle) pumps that blood to the rest of the body.

But in a baby with HLHS, the left side of the heart is very weak. So it can't do that job. So what happens? The right side of the heart has to do both jobs on its own . That means that the right ventricle has to pump blood to the lungs, while also pumping blood to the rest of the body.

How does this happen? When a baby is in the womb, there is a temporary connection between the two main blood vessels in the heart. It is called the ductus arteriosus.It's like a 'shortcut'. This 'shortcut' is essential for a baby with HLHS to survive after birth. Because blood flows through this tube to the body. Normally, this tube closes a few days after a baby is born. But if this tube closes in a baby with HLHS, there is no way for blood to flow to the body. Therefore, if this condition is not treated, a baby will only have a few days to live.

How do you know if your baby has this condition? What are the symptoms?

If a newborn baby has HLHS, sometimes the symptoms are not visible at first. But these symptoms can appear within a few hours or days. It is very important for parents to be aware of this.

Why does this happen to babies? What is the reason?

This question is on every parent's mind. It's normal to wonder, "Why did this happen to our baby? Did we do something wrong?"

But the truth is, in most cases, there is no specific cause for HLHS . That is, it is not something that is caused by the mother or father. Sometimes, genetic factors can play a role. That is, certain genetic changes in the family may increase the risk. Babies with other genetic conditions, such as Turner syndrome or trisomy 18, are also at risk for HLHS.

How do doctors accurately diagnose this disease?

Fortunately, with today's advanced technology, this disease can be diagnosed before the baby is born, that is, during pregnancy . If an abnormality is found in the heart during a routine prenatal ultrasound scan, your doctor will refer you to a specialist and ask you to do a fetal echocardiogram . This allows you to see the structure and function of the baby's heart very clearly.

To diagnose the condition after the baby is born, the doctor will look at the baby's symptoms and listen to the chest with a stethoscope to see if there is an abnormal heart sound (heart murmur). Then, several tests will be performed to confirm the condition, such as:

• Chest X-ray: A chest X-ray can check the size and shape of the heart and lungs.
• Echocardiogram: This is the most important test. It's like a video scan of the heart. The heart's chambers, valves, and blood vessels are all clearly visible. This is what confirms whether you have HLHS.
• Electrocardiogram (EKG): A test that measures the electrical activity of the heart.
• Pulse oximetry screening: A small clip-like device is placed on the baby's finger or ear to measure the amount of oxygen in the blood. This value is low in babies with HLHS.

Is there a treatment for this condition? Can the baby be saved?

Yes, this is a very serious condition, but there are treatments. But this is not a disease that can be cured with medication. To save the baby's life, a complex series of surgeries consisting of several stages must be performed.

Step One: Stabilizing the Baby

Before surgery, the baby needs to be stabilized. The first step is to keep the ductus arteriosus , the 'shortcut' blood vessel we talked about, open. A drug called prostaglandin is given intravenously. Other drugs may also be used to help the baby's heart beat, and a ventilator may be used to help the baby breathe.

Step Two: Three-Stage Surgical Series

The main goal of this series of surgeries is to completely bypass the weak left side and give the stronger right side of the heart (the right ventricle) the job of pumping blood to the entire body. It's like redirecting blood flow in a completely different direction.

1. Norwood procedure: This is done within the first two weeks of a baby's birth. This is a very complex, serious surgery. Here, surgeons:

• The underdeveloped aorta is reconstructed.
• A special tube (shunt) is inserted to send blood from the right ventricle directly to the lungs.
• In this way, the heart's "tubular system" is modified so that the right ventricle can pump blood to the entire body and lungs.

2. Glenn surgery (Bidirectional Glenn shunt operation): This is done when the baby is between 4 and 6 months old . Here:

• The tube (shunt) inserted during the first surgery is removed.
• Oxygen-poor blood from the upper part of the body (from a vein called the superior vena cava) is connected directly to the lungs.
• This greatly reduces the burden on the right ventricle, because now it doesn't have to pump blood from the upper body, it goes directly to the lungs.

3. Fontan procedure: This is the final stage. It is performed between the ages of 18 months and 4 years . Here:

• Oxygen-poor blood from the lower part of the body (from a vein called the inferior vena cava) is connected directly to the lungs.
• After this surgery, all the oxygen-poor blood from the body goes directly to the lungs. The right ventricle of the heart only has to pump clean, oxygen-rich blood from the lungs to the entire body.

After these three surgeries are complete, the baby's circulatory system begins to function in a completely new way.

What are the complications of treatment?

Although these surgeries are life-saving, they are very complex and can carry risks and complications. Problems can arise during and after surgery.

• The right ventricle becomes weak due to the heavy load it has to bear.
• Blood leakage from heart valves.
• Liver diseases.
• Abnormal heart rhythms.
• Blood clotting.
• Infections.
• Difficulty eating.
• Seizures.
• Effects on the kidneys.

The doctor will discuss all of these risks with you in detail. The medical team will be monitoring the baby very closely as they make this journey.

Is a Heart Transplant a Good Option?

In some cases, if the baby's heart condition is very complex or if doctors think the baby will not survive the surgery, they may recommend a heart transplant . But they have to wait until a compatible heart becomes available. Also, after a heart transplant, the baby will have to take immunosuppressive drugs for the rest of their life.

If a baby has this condition, what should we as parents know?

This journey is challenging, but with proper medical supervision and care, children with HLHS can lead good lives.

• Lifelong medical supervision: After surgery, the child will need to visit a cardiologist for the rest of their life. They should have check-ups at least once a year.
• Medications: Many children will need to take heart medications throughout their lives.
• Antibiotics before other surgeries: Before any other surgery, such as tooth extraction, you need to take antibiotics to prevent heart infections (endocarditis).
• Physical activity: Your child's physical activity may need to be limited. Strenuous activities, such as competitive sports, are generally not recommended. Ask your doctor for advice on this.
• Your mental health: This journey is very tiring for parents. It can be stressful. So, talk about your feelings with your husband/wife and family. Seek counseling if necessary. Only when you are strong will you be able to take good care of your child.