ACYANOTIC (LEFT-to-right shunting) defects are the most common. The freshly-oxygenated blood is being backwashed from the left side of the heart to the right. The systemic pressure is greater than pulmonic. NO venous blood (deoxygenated blood) enters the systemic circulation. All of the blood returning to the right side of the heart passes through the lungs. The LUNGS are overloaded.
With mild acyanotic cases, the defect will often heal on its own with time. Medical management (Lanoxin, Lasix) may or may not be required. With severe cases, surgery is required.
Examples of acyanotic (left-to-right) heart defects:
Ventricular septal defect (VSD)
Atrial septal defect (ASD)
Patent ductus arteriosus (PDA)
Atrioventricular septal defect (AVSD) (endocardial cushion defect)
Manifestations of acyanotic defects:
Not always apparent at birth
INCREASED pulmonary blood flow (LEFT-to-right defect think LUNGS) - at risk for pulmonary HTN
Enlarged heart (right, sometimes left)
Congestive heart failure
Enlarged liver, dyspnea, tachypnea, intercostal retractions, poor growth, frequent respiratory infections
With CYANOTIC lesions, on the other hand, there is RIGHT-to-left shunting. The pulmonic pressure is greater than systemic pressure. Venous blood (deoxygenated blood) bypasses pulmonary circulation and goes directly to the left side of the heart to be pumped into the systemic circulation. Cyanotic heart defects are generally more complex than acyanotic defects and have a combination of defects. Surgery is needed to repair.
There is an obstruction on the right side of the heart. Pressures from obstructed blood in the right side of the heart exceed those in the left. The unoxygenated venous blood flows directly from the right sided chambers to the left-sided chambers (right to left shunt) while bypassing the lungs. Unoxygenated blood (venous blood) enters the systemic circulation and there is mixing of pure oxygen-rich blood with venous blood.
, remember CPR
yanotic heart defect (can make a child turn blue)
ulmonic pressure greater than systemic
Examples of cyanotic (right-to-left) heart defects:
Usually the ones starting with a "T" -
Tetralogy of Fallot (TOF)
Transposition of the Great Arteries (TGA)
Total Anomalous Pulmonary Venous Return
Hypoplastic Left Heart Syndrome (HLHS)
Manifestations of cyanotic heart (right-to-left shunt) defects:
Cyanotic at birth ("blue baby")
Symptomatic soon after birth
DECREASED pulmonary blood flow.
Hope this helps to clear up some of the confusion