LAUSR

Sir, A 12-year-old asymptomatic boy was referred for assessment with a history of a heart murmur noted at 2 years of age but subsequently lost to follow-up. Physical examination showed normal growth and development and an unremarkable cardiorespiratory exam. He had participated in multiple sports with no shortness of breath, chest pain, or syncope. An echocardiogram showed lack of bifurcation of the main pulmonary artery with smooth continuation into the right pulmonary artery (RPA), mild hypoplasia of left pulmonary artery (LPA) measuring 7 mm in diameter, normal caliber of RPA (20 mm diameter), and no intracardiac defects. There was no obvious gradient across the pulmonary artery (PA) branches [Figure 1]. The predicted right ventricular systolic pressure based on the tricuspid regurgitation jet was normal; the predicted PA end diastolic pressure based on the mild pulmonary insufficiency jet was normal and he had normal biventricular function. A Technetium-99m macroaggregated albumin scint igraphy with single-photon emission computed tomography (CT) acquisition revealed mildly asymmetric flow to the LPA (29%) and the RPA (71%) with no peripheral perfusion defects [Figure 2]. Chest CT with intravenous contrast including awake dynamic airway imaging during inspiration and expiration showed normal aortic Left pulmonary artery sling without symptoms