Erica Thayer   |   August 12, 2019

What is HLHS?


HLHS Explained 

HLHS stands for Hypoplastic Left Heart Syndrome. It is a part of the 25% of critical congenital heart defects and requires life saving surgeries in the early days of life. It alters the normal flow of blood through the heart. HLHS affects many structures on the left side of the heart like the left ventricle, mitral valve and aortic valve. These aspects of the heart are severely underdeveloped or not developed at all. In other words, it leaves the patient with half a functioning heart. 

A Normal Heart vs HLHS Heart 

In a normal heart, the right side is responsible for pumping oxygen-poor blood from the heart to the lungs to receive oxygen. The left side’s job is to pump the now oxygen-rich blood to the rest of the body. 

In a HLHS heart, the left side is underdeveloped and therefore cannot function properly. It is unable to do its job and therefore there is poor blood flow to the rest of the body — i.e. the brain, other organs, limbs, etc. This leaves the right side to try and pump blood to both the lungs and full body which is not ideal or sustainable long-term. 

HLHS History 

What today is known as HLHS was originally termed hypoplasia of the aortic tract complex in 1952. The original discovery was followed by the study of Noonan and Nadas who introduced the term Hypoplastic Left Heart Syndrome in 1958. This was to collectively describe the people in the study with multiple malformations in the left side of the heart. In 1983, the first successful use of the Norwood procedure was conducted on an HLHS patient.  

Saving Surgeries + Side Effects

Before surgeries like the Norwood, Glenn and Fontan, HLHS was a death sentence. These blue babies would die shortly after birth, leaving the deep pain of loss in their families’ lives. Thanks to research and experimentation, surgeries and advanced medical interventions were developed to prolong the lives of those with HLHS. However, they are still only temporary fixes to hold over until the next intervention. These surgeries, though life saving, create problems down the line. The Fontan series is thought to create liver problems and have negative effects on other organs in the body. There is no cure for CHD. The long-term impact of these side effects are still largely unknown as the oldest people alive with HLHS are only in their 30s and 40s. 

We need a cure for HLHS. We need a cure for CHD. The time is now to make a change in the way we approach the treatment of CHD. We have set a goal to collaborate with researchers all over the world and grow a heart made from a patient’s own stem cells by 2040. We believe everyone deserves a long and healthy life without limits. Will you join us

Read more about Project Heart's mission to find a cure for CHD!

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