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.

Introduction: Scimitar syndrome is a rare congenital form of partial anomalous pulmonary venous return characterized by right pulmonary venous drainage into the inferior vena cava. This abnormal shunting leads to 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. Objectives: This systematic review aims to describe how congenital cardiopulmonary abnormalities in patients with Scimitar syndrome contribute to atrial remodeling and the development of atrial and supraventricular arrhythmias. Methods A literature review search was conducted in PubMed. Relevant data were extracted after screening titles, 308 abstracts were assessed using inclusion and exclusion criteria. Full text screening was performed for 94 articles, Inclusion criteria consisted of patients with Scimitar syndrome. Exclusion criteria included literature review, animal studies and non-English articles. Results: Studies consistently showed that Scimitar syndrome is associated with right atrial enlargement and atrial remodeling due to chronic right-sided volume overload. These changes were linked to an increased burden of atrial and supraventricular arrhythmias, most commonly atrial fibrillation and atrial flutter. Arrhythmia risk was greater in patients with associated abnormalities such as atrial septal defects or pulmonary hypertension. Discussion and Conclusion: Scimitar syndrome often presents with atrial remodeling and cardiac abnormalities that increase the risk of arrhythmias, especially atrial fibrillation and atrial flutter. Given that scimitar syndrome can remain undiagnosed until adulthood, future studies should focus on the specific predictors for arrhythmia development to improve long-term electrophysiological outcomes.