A 7-year-old girl is brought to the physician by her mother for a follow-up examination. The following schematic represents the oxygen tension (pO2) within her cardiopulmonary circulation. Which of the following is the most likely explanation for these findings?
Atrial septal defect (left-to-right shunt)
Atrial septal defect (right-to-left shunt)
Patent ductus arteriosus
Ventricular septal defect (left-to-right shunt)
Ventricular septal defect (right-to-left shunt)
