Persistent Left Superior Vena Cava in Pacemaker Implantation for Digoxin-Induced Complete Heart Block: Clinical Considerations and Challenges.

Duplication of the superior vena cava is a rare congenital anomaly. Although often asymptomatic, this anatomical variation can complicate cardiovascular procedures, particularly those involving central venous access. We present the case of an 82-year-old female with multiple comorbidities, who was incidentally found to have a persistent left superior vena cava (PLSVC) during pacemaker implantation for digoxin-induced complete heart block. The initial pacemaker implantation on the left side was unsuccessful due to resistance, which led to the identification of PLSVC via contrast-enhanced CT scan. The procedure was successfully completed by shifting the implantation to the right side. This case highlights the importance of recognizing venous anomalies such as PLSVC during interventional procedures, as early identification can prevent complications and inform surgical strategy. Awareness of such congenital variations is essential, particularly in patients with complex medical histories.