Review Question - QID 109382

A 30-month-old boy presents to the pediatrician with his parents for a new patient appointment. The patient was recently adopted from India and he has medical records demonstrating a past medical history of recurrent otitis media, recurrent sinusitis, and 2 episodes of pneumonia. The parents report that the patient has been well since arriving in the United States although they have noticed that he becomes dizzy and needs to squat down when he becomes upset. They also sometimes notice a bluish hue around his mouth during these episodes. Nothing is known about the patient’s family history. His temperature is 98.4°F (36.9°C), blood pressure is 65/43 mmHg, pulse is 128/min, and respirations are 32/min. On physical exam, the patient has low-set ears, upslanting palpebral fissures, and a cleft lip. He has a harsh systolic ejection murmur at the left upper sternal border. The patient becomes agitated during the administration of several immunizations, and his lips are noted to have a bluish discoloration. The patient’s chest radiograph can be seen in Figure A. An analysis of this patient's physiology would most likely reveal which of the following findings?