Circular Shunt: A Loop Not to Be Ignored.

A circular shunt, initially described by Shone et al. in 1962, refers to abnormal blood recirculation through complete intracardiac or intra- and extracardiac communications, bypassing the capillary beds. This pathophysiological condition is most commonly associated with complex congenital heart defects, such as Ebstein's malformation, pulmonary atresia, Gerbode defect, and so on. Circular shunts significantly disrupt cardiac output and systemic perfusion, leading to heart failure, hypotension, and organ dysfunction. Clinical presentation varies from severe neonatal distress to progressive heart failure in older children. Diagnosis requires a high index of suspicion and careful evaluation, and its management focuses on interrupting or reducing the shunt through surgical repair or transcatheter intervention or, in some cases, medical therapy. Early diagnosis, particularly in prenatal cases, and timely intervention are crucial for improving outcomes in affected neonates.