What is HLHS?

What is HLHS:

HLHS is a congenital (present at birth) defect in which the left side of the heart does not form correctly.  The left side of the heart is responsible for pumping oxygen-rich blood to the entire body except for the lungs  Babies do well in the womb, but once they’re born it becomes a problem.  There are 2 openings in the heart (PDA and PFO) that naturally close a few days after a baby is born, and when these close in a HLHS baby, oxygen-rich blood can no longer get to the body.


About 960 babies in the US are diagnosed with HLHS per year, which is about 1:4300 babies.  About 2/3 are boys, and 1/3 affect girls.


Causes are unknown, however, some causes can be from genes, chromosomes, or environmental factors.  However, most of the time the cause is unknown.


Without intervention, HLHS is fatal.  Parents are often given 3 options: termination, palliative surgeries/transplant, and comfort care.  It is important for parents to understand that surgery does not cure the baby.  There is no cure in current medicine for HLHS.  Surgeries prolong life until a transplant would be needed, which often (not always) occurs in the teen to college years.  Babies who have surgeries will have lifelong complications, however, the severity of those complications can vary from child to child.  Complications can include but are not limited to: chronic GI complications, chronic liver problems, chronic kidney problems, chronic lung problems, heart failure, chronic fluid retention in the lungs, abdomen, and lungs, arrhythmias, strokes, developmental delays, psychological problems, and death.


Cardiol, P. (August 27, 2016). Hypoplastic Left Heart Syndrome: Exploring a Paradigm Shift in Favor of Surgery. Pediatric Cardiology. DOI: 10.1007/s00246-016-1455-y. Retrieved from     

Centers for Disease Control and Prevention. (2016). Facts About Hypoplastic Left Heart Syndrome. Retrieved from www.cdc.gov/ncbddd/heartdefects/HLHS.html

University of Iowa Health Care. (2016). Hypo plastic Left Heart Syndrome. Retrieved from