Decreased pulmonary blood flow, right-to-left shunting, and deoxygenated blood reaching the systemic circulation are characteristic of:

Question

Options

• ATetralogy of Fallot
• BVentricular septal defect
• CPatent ductus arteriosus
• DTransposition of the great arteries

• A
  92% (59)
• B
  2% (1)
• C
  2% (1)
• D
  5% (3)

Explanation

(A) Tetralogy of Fallot is the most common cyanotic heart defect, which includes a VSD, pulmonary stenosis, an overriding aorta, and ventricular hypertrophy. The blood flow is obstructed because thepulmonary stenosis decreases the pulmonary blood flow and shunts blood through the VSD, creating a right-to-left shunt that allows deoxygenated blood the reach the systemic (B) A VSD alone creates a left-to-right shunt. The pressure in the left ventricle is greater than that of the right; therefore, the blood will shunt from the left ventricle to the right ventricle, increasing the blood flow to the lungs. No deoxygenated blood will reach the systemic circulation. (C) In patent ductus arteriosus, the pressure in the aorta is greater than in the pulmonary artery, creating a left-to-right shunt. Oxygenated blood from the aorta flows into the unoxygenated blood of the pulmonary artery. (D) Transposition of the great arteries results in two separate and parallel circulatory systems. The only mixing or shunting of blood is based on the presence of associated lesions.

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