Late Presentation of Isolated Persistent Left Superior Vena Cava with Absent Right Superior Vena Cava Manifesting as Heart Failure: A Case Report.

Background: Persistent left superior vena cava (PLSVC) with absent right superior vena cava (RSVC) is a rare congenital venous anomaly, typically asymptomatic and discovered incidentally. In rare cases, it may contribute to hemodynamic disturbances and arrhythmias, potentially leading to heart failure, especially when associated with other cardiac anomalies or conduction abnormalities. Case Presentation: We report the case of a 45-year-old male who presented with progressive symptoms of heart failure, including dyspnea, fatigue, and reduced exercise tolerance. Initial workup revealed an unexplained dilated coronary sinus and reduced left ventricular function with dilated heart chambers. Further imaging with contrast-enhanced echocardiography and CT angiography confirmed the presence of a PLSVC draining into the coronary sinus with absence of right superior vena cava. No other congenital heart defects were identified like coronary sinus atrial septal defect (ASD). The delayed diagnosis of PLSVC likely contributed to chronic atrial stretch, arrhythmia development- atrial fibrillation in this case, and eventual heart failure symptoms. Conclusion: This case highlights the importance of considering vascular anomalies like PLSVC in the differential diagnosis of unexplained heart failure or dilated coronary sinus. Early detection through appropriate imaging can guide management and potentially prevent progression of symptoms.