A cyanotic heart defect is a group-type of congenital heart defects. The patient appears blue (cyanotic), due to deoxygenated blood bypassing the lungs and entering the systemic circulation. This can be caused by right-to-left or bidirectional shunting, or malposition of the great arteries.

Defects in this group, which account for approximately 25% of all CHD's, include:

• dextro-Transposition of the great arteries (d-TGA)
• Hypoplastic left heart syndrome (HLHS)
• Pulmonary atresia (PA)
• Tetralogy of Fallot (ToF)
• Tricuspid atresia
• Truncus arteriosus

Congenital heart disease