Congenital Heart Disease USMLE Step 1 Practice Question
A 3-year-old girl presents with cyanosis that worsens with crying and exertion. Physical examination reveals a systolic ejection murmur at the left upper sternal border and a right ventricular heave. Chest X-ray shows a boot-shaped heart with decreased pulmonary vascular markings. Which of the following is the pathophysiologic basis for her cyanosis?
Answer choices
- APulmonary vascular obstruction from increased blood flow
- BDecreased systemic vascular resistance
- CComplete mixing of systemic and pulmonary circulations
- DRight-to-left shunt due to right ventricular outflow obstructionCorrect answer
- ELeft-to-right shunt with pulmonary edema
- FPulmonary atresia with ventricular septal defect
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