Cyanotic heart defects are abnormal openings between the heart
chambers that allow oxygen-poor blood from the right side of the heart to mix
with oxygen-rich blood from the left side of the heart. When a large amount of
oxygen-poor blood mixes with oxygen-rich blood, it causes a bluish tint
(cyanosis) in the skin, lips, and nail beds.
John Pope, MD - Pediatrics & Larry A. Latson, MD - Pediatric Cardiology