Snapshot A neonatal boy is born to a 37-year-old mother via normal spontaneous vaginal delivery. His mother has type 2 diabetes and hypertension. Since birth, he has had trouble feeding, seems to be constantly tachypneic, and has increasingly blue lips. He is immediately given prostaglandin E, and an echocardiogram is obtained, revealing transposition of the great vessels. He is scheduled for surgical repair. Introduction Clinical definition a congenital heart defect in which the aorta leaves the right ventricle and the pulmonary trunk leaves the left ventricle, resulting in the complete separation of the systemic and pulmonary circulations Epidemiology demographics male > female present at birth most common cyanotic lesion presenting immediately after birth risk factors maternal diabetes maternal smoking advanced maternal age Etiology failure of neural crest cells to migrate Pathogenesis failure of the aorticopulmonary septum to spiral results in complete separation of the systemic and pulmonary circulations infants survive only if a shunt between the two circulations exist, to mix oxygenated blood into the systemic circulation patent ductus arteriosus (PDA) ventricular septal defect (VSD) atrial septal defect (ASD) patent foramen ovale (PFO) Associated conditions VSD coarctation of the aorta Prognosis infants experience severe cyanosis and tachypnea as the ductus arteriosus closes in the newborn period Presentation Symptoms early and progressive cyanosis that does not correct with oxygen signs of heart failure tachypnea sweating poor feeding Physical exam cardiac loud and single S2 heart sound may have a soft systolic ejection murmur may have harsh holosystolic murmur if patients have VSD central cyanosis Imaging Radiography indication for all patients recommend views chest findings cardiomegaly egg-on-a-string appearance narrowed mediastinum Echocardiography indication performed as a diagnostic test most specific test findings pulmonary trunk arising from the left ventricle aorta arising from the right ventricle Studies Making the diagnosis based on clinical presentation and echocardiography in some cases, patients may be diagnosed prenatally with fetal echocardiography Differential Tetralogy of Fallot distinguishing factor tet spells (cyanosis) that are resolved when placed in knee-chest position Treatment Medical prostaglandin E1 indication for all neonates mechanism of action maintains a patent ductus arteriosus for adequate lower extremity perfusion Operative balloon atrial septostomy (Rashkind procedure) indication for all patients performed for temporary mixing prior to definitive surgical repair arterial switch surgical repair indication for all patients as definitive treatment commonly performed in the first month of life Complications Heart failure Sudden cardiac death