A to Z: Hypoplastic Left Heart Syndrome

May also be called: HLHS

Hypoplastic (HI-puh-plas-tik) left heart syndrome (HLHS) is a rare and serious defect in which the structures of the left side of the heart (the left ventricle, the mitral valve, and the aortic valve) are underdeveloped. As a result, blood cannot be adequately pumped throughout the body.

More to Know

Hypoplastic left heart syndrome is present at birth (congenital) and has no known cause. It is usually diagnosed within the first few days of life. Without surgery to repair the heart, HLHS is fatal.

Symptoms of HLHS include blue or gray skin color (cyanosis), rapid breathing, pounding heart, shortness of breath, cold hands and feet, weak pulse, unusual drowsiness and poor feeding.

Once diagnosed with HLHS, most babies will undergo a series of three operations beginning shortly after birth and ending at 3 years of age. For some babies, heart transplant is the best option if a donated organ is available.

Keep in Mind

While many babies now survive HLHS, they need to be monitored closely by a cardiologist for the rest of their lives. Many complications can occur with HLHS and sometimes additional heart surgery or even heart transplant may be necessary as children born with HLHS get older.

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.