Anomalous Coronary Venous Drainage to the Right Atrium: A Case Report.

Anomalies of the coronary venous system are rare and may have important implications for cardiac imaging and invasive procedures. We report a case of anomalous coronary venous drainage identified on chest computed tomography angiography (CTA) in a 53-year-old man undergoing routine follow-up after surgical repair of a type A aortic dissection. Imaging demonstrated a dilated coronary sinus, secondary to distal narrowing, with dilation of the great cardiac vein suggestive of compensatory redistribution of venous return. Additionally, the left marginal vein was observed to drain directly into the right atrium, bypassing the coronary sinus. An incidental persistent left superior vena cava draining the coronary sinus into the left brachiocephalic vein was also identified, with a normal right superior vena cava present. The patient was asymptomatic, and no intervention was required. This case highlights a rare variant of coronary venous anatomy, with potential implications for central venous access, cardiac device implantation, and surgical planning. Recognition of such anomalies through careful cross-sectional imaging is essential to avoid diagnostic pitfalls and to ensure safe procedural management.