Successful Management of a Neonate With Tricuspid Atresia, Double Outlet Right Ventricle, and L-malposed Great Arteries.

A neonate with prenatally suspected complex single ventricle physiology was found after birth to have tricuspid atresia with a large ventricular septal defect, double outlet right ventricle, L-malposed great arteries, and severe subpulmonary stenosis. The infant presented at term via cesarean delivery for breech presentation with cyanosis, poor tone, and absent spontaneous respirations, requiring immediate positive pressure ventilation and initiation of prostaglandin E₁ to support ductal patency during hemodynamic stabilization. Early transthoracic echocardiography confirmed complex single ventricle anatomy with a hypoplastic right ventricle, L-malposed great arteries, and a restrictive subpulmonary outflow tract, consistent with a Type IIIb tricuspid atresia subtype with reduced pulmonary blood flow. The patient underwent staged surgical palliation beginning with a 3 mm modified Blalock-Taussig shunt via central sternotomy at one month of age, which was complicated by medically managed necrotizing enterocolitis but otherwise followed by a stable interstage period with appropriate oxygen saturations. The patient had low-normal branch pulmonary arteries, and there was no patent ductus arteriosus. At five and a half months, she underwent a hemi-Fontan procedure with bilateral pulmonary artery patch augmentation, atrial septectomy, and shunt takedown, resulting in a patent cavopulmonary connection and adequate systemic output despite transient postoperative ventricular dysfunction. The child was subsequently discharged on standard heart failure and antiplatelet therapy, with gradual weaning of afterload reduction and diuretics as ventricular function improved and oxygen saturation targets were maintained. This case illustrates how detailed anatomical characterization of tricuspid atresia, particularly the relationship of the great arteries and degree of pulmonary outflow obstruction, guides selection and timing of staged palliation. It also underscores the value of coordinated prenatal and postnatal evaluation, early initiation of prostaglandin therapy, and close interstage monitoring in achieving a favorable early outcome in a rare and complex tricuspid atresia subtype that remains eligible for eventual Fontan completion.