A 21-year-old patient with a D-transposition of the great arteries and a single coronary ostium underwent an atrial switch operation as newborn (Senning correction at 6 days of life in 1992). For an unrelated oncological evaluation, she underwent a recent F-FDG PET/CT. The myocardial uptake was clearly more intense in the morphological right ventricle, as this ventricle has become the systemic ventricle. On the contrary, the morphological left ventricle showed a very faint FDG uptake. This case illustrates the physiological changes related to a previous cardiac surgery.