I have been working on this post since Jan, gathering info since this heart defect hits close to home for my family, and because I always been the go-to researcher for my family. It's what I do well.
Hypoplastic Left Heart Syndrome (HLHS) is a rare and serious congenital heart defect that affects about 1 in every 4,000 newborns. It develops before birth, during the early stages of fetal growth, and is usually diagnosed shortly after delivery or sometimes even during pregnancy through advanced prenatal screening.
In HLHS, the left side of the heart is critically underdeveloped. This includes the left ventricle, mitral valve, aortic valve, and ascending aorta. All vital components responsible for pumping oxygen-rich blood to the body. Because of this underdevelopment, the heart can't function properly on its own.
How Serious Is It?
Without treatment, HLHS is fatal, often within the first few days or weeks of life. But over the past few decades, surgical advancements have turned what was once a uniformly deadly diagnosis into a condition that, while still life-threatening, is treatable and survivable.
The Treatment Path: A Long Road
Babies born with HLHS typically undergo a series of three major open-heart surgeries within the first few years of life:
Norwood Procedure – Within the first week or two after birth
Glenn Procedure – Around 4 to 6 months old
Fontan Procedure – Usually between 2 and 4 years old
These surgeries work together to reroute blood flow, allowing the right side of the heart to take over for the missing left side. After the Fontan, the blood from the body flows directly to the lungs without passing through a ventricle first, relieving strain on the heart.
But even after this third surgery, HLHS is not “cured.” Most children live with a single-ventricle physiology, and over time, the heart may begin to wear down. Many children eventually need a heart transplant later in life.
The Human Side of HLHS
Behind every diagnosis is a child fighting to grow, laugh, and live. There is a family holding their breath through every scan, surgery, and setback.
Tomorrow morning, my 4-year-old cousin will undergo his third open-heart surgery: the Fontan Procedure. This is the final planned surgery in the HLHS surgical journey, and it’s a major turning point. He’s already made it through the Norwood and the Glenn. That alone makes him a warrior. But tomorrow is another battle. And after that? He will likely need a heart transplant in the near future.
He’s an incredibly brave 4-year-old, and so are his parents. HLHS isn’t just a medical condition. It’s a daily fight for strength, stability, and hope. Watching a child go through this changes you.
Why Awareness Matters
Because HLHS is rare, many people, including expectant parents and even some medical professionals, aren’t aware of it until they’re living it. I never heard of it until 4 years ago.
Early diagnosis, proper care, and continued research can make all the difference. HLHS kids are warriors. Their hearts may be half the size, but their strength is twice as powerful. 💙
