Review Question - QID 109717

A newborn boy is assessed in the newborn nursery due to central cyanosis that does not respond to oxygen therapy. The patient was born to a G1P1 mother at 39 weeks gestation. The mother had diabetes that was managed with exercise and insulin during the pregnancy. The mother has never been vaccinated and did not follow routine prenatal care. The newborn's temperature is 99.5°F (37.5°C), blood pressure is 70/30 mmHg, pulse is 160/min, respirations are 27/min, and oxygen saturation is 80% on room air. The initial workup of the patient includes a chest radiograph seen in Figure A as well as lab values as seen below.

Hemoglobin: 14 g/dL
Hematocrit: 42%
Leukocyte count: 6,500/mm^3 with normal differential
Platelet count: 197,000/mm^3

Serum:
Na+: 139 mEq/L
Cl-: 101 mEq/L
K+: 4.3 mEq/L
HCO3-: 24 mEq/L
BUN: 12 mg/dL
Glucose: 99 mg/dL
Creatinine: 0.5 mg/dL
Ca2+: 10.0 mg/dL
AST: 12 U/L
ALT: 10 U/L

An electrocardiogram is obtained as seen in Figure B. Which of the following is the most likely diagnosis?