Q. You are called to the newborn nursery to evaluate a 1-day-old male who has demonstrated a slight blue tint to his skin (cyanosis). He is a term infant, although the patient’s mother did not receive any significant prenatal care. Her vaginal delivery was uncomplicated, and the patient had a 5-minute APGAR score of 7, with points deducted for moderate peripheral cyanosis, decreased reflex irritability, and decreased tone. The patient is otherwise doing well with the exception of mild cyanosis noted by nursery staff associated with oral feedings. Delivery height and weight were both documented to be in the 50th percentile. On physical examination, he is a healthy appearing infant, in no acute distress, and with no visible asymmetry. The patient's blood pressure is 90/60 mm Hg, pulse is 120/min, respiratory rate 40/min, and oxygen saturation is 96 percent on room air. His head and neck exam are normal, and his lung fields are clear bilaterally. Cardiac examination demonstrates regular rate and rhythm, with a normal first heart sound, and a single second heart sound that is louder than expected. A crescendo-decrescendo murmur with harsh systolic ejection quality is best heard at the left upper sternal border and radiates posteriorly. You also note a prominent ventricular impulse and palpate a systolic thrill. A chest x-ray (CXR) is ordered (see image) to assist with your assessment. Based on this patient’s history and physical examination, and CXR, what is the most likely diagnosis?