Atrial Remodeling and Arrhythmia in Scimitar Syndrome: A Literature Review

Scimitar syndrome is a rare congenital form of partial anomalous pulmonary venous return characterized by right pulmonary venous drainage into the inferior vena cava, causing right-sided volume overload and increased risk of supraventricular arrhythmias, particularly in adolescents and adults. However, existing studies do not clearly describe reported arrhythmia patterns or how heart rhythm changes over time. This structured literature review aimed to characterize the reported atrial and supraventricular arrhythmias and conduction disturbances in patients with Scimitar syndrome and examine their relationship with atrial remodeling, hemodynamic burden, associated structural abnormalities, and surgical or catheter-based intervention. PubMed, Embase, Web of Science, and the Cochrane Library were searched from September 2026. Of 308 abstracts, 42 articles met the inclusion criteria (Scimitar syndrome patients, with broader PAPVR populations included as contextual evidence; literature reviews, abstract only publications, animal studies and non-English articles were excluded). Studies consistently showed that Scimitar syndrome is associated with right-sided volume overload linked to increased atrial and supraventricular arrhythmias, most commonly atrial fibrillation and flutter, with greater risk in patients with associated atrial septal defects or pulmonary hypertension. Because Scimitar syndrome can remain undiagnosed until adulthood, future studies should identify specific predictors of arrhythmia development to improve long-term electrophysiological outcomes.