Definition of Cyanotic heart disease:

Cyanotic heart disease is a heart defect, present at birth (congenital), that results in low blood oxygen levels. There may be more than one defect. The defect affects the structure or function of the heart or vessels.

Causes, incidence, and risk factors:

Heart defects can change the way blood flows around the heart and lungs. This abnormal blood flow (called right-to-left shunt) causes too little oxygen to move through the blood to the rest of the body.

Cyanotic heart disease causes the child's skin to look blue (cyanosis). This bluish color is most often seen on the lips, fingers, and toes, or during exercise. Some heart defects cause major problems immediately after birth, and some cause few, if any, problems until adulthood.

Congenital heart defects that may cause cyanosis include:

• Tetralogy of Fallot
• Transposition of the great vessels
• Ebstein's anomaly
• Tricuspid atresia (a deformity of the tricuspid heart valve)
• Total anomalous pulmonary venous return
• Pulmonic stenosis with an atrial or ventricular septal defect
• Truncus arteriosus
• Hypoplastic left heart syndrome
• Critical pulmonary valvular stenosis
• Coarctation of the aorta
• Interrupted aortic arch
• Pulmonary valve atresia

Most congenital heart diseases affect only the heart, but some conditions many affect many organs. Most congenital heart diseases are not cyanotic.

Some cyanotic heart diseases are caused by drug use, chemical exposure, or infections (such as rubella) during pregnancy.

Cyanosis may also be caused other conditions that are usually not associated with congenital heart disease. Such conditions may include lung disease, abnormal forms of hemoglobin (the protein that carries oxygen through the blood), dehydration, and hypoglycemia.

Cyanosis is a sign of Eisenmenger syndrome, a condition that occurs in patients with congenital heart disease. Eisenmenger syndrome occurs as a complication of increased blood flow from the left side of the heart directly to the lungs. This results in severe lung diseases and increased pressures on the right side of the heart.