A 3-day-old infant with a single second heart sound has had progressively deepening cyanosis since birth but no respiratory distress. Chest radiography demonstrates no cardiomegaly and normal pulmonary vasculature. An electrocardiogram shows an axis of 120° and right ventricular prominence. Which of the following congenital cardiac malformations is most likely responsible for the cyanosis?

a. Tetralogy of Fallot

b. Transposition of the great vessels

c. Tricuspid atresia

d. Pulmonary atresia with intact ventricular septum

e. Total anomalous pulmonary venous return below the diaphragm

the answer is below…

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