At first, a newborn with hypoplastic left heart may appear normal. Symptoms usually occur in the first few hours of life, although it may take up to a few days to develop symptoms. These symptoms may include:

• Bluish (cyanosis) or poor skin color
• Cold hands and feet (extremities)
• Lethargy
• Poor pulse
• Poor suckling and feeding
• Pounding heart
• Rapid breathing
• Shortness of breath

In healthy newborns, bluish color in the hands and feet is a response to cold (this reaction is called peripheral cyanosis).

However, a bluish color in the chest or abdomen, lips, and tongue is abnormal (called central cyanosis). It is a sign that there is not enough oxygen in the blood. Central cyanosis often increases with crying.

A physical exam may show signs of heart failure:

• Faster-than-normal heart rate
• Lethargy
• Liver enlargement
• Rapid breathing

Also, the pulse at various locations (wrist, groin, and others) may be very weak. There are usually (but not always) abnormal heart sounds when listening to the chest.

Tests may include:

• Cardiac catheterization
• ECG
• Echocardiogram
• X-ray of the chest