"The Gold standard is surgery -- arterial switch procedure," said Dr. Daphne Hsu, division chief of pediatric cardiology at Montefiore Medical Center in New York. "The procedure has to be done before the child is 1 month old, because then the heart starts to change and adjust to the circulation, and the pressure in the heart drops."
Newborn's Family Learns Pre-Existing Conditions Apply at Birth - ABC News