Abstract 4346607: Incidental finding of a persistent left superior vena cava during pacemaker placement: a case report

Background: The incidence of persistent left superior vena cava (PLSVC) in the general population is estimated to be between 0.3% and 0.5%, which equates to approximately 1 in every 200 to 325 healthy individuals. Aims: To highlight the technical challenges posed by this congenital venous anomaly during cardiac pacing procedures, particularly in venous access and lead positioning. To raise awareness of the need for a multidisciplinary approach, involving cardiology, cardiovascular imaging, and cardiothoracic surgery, to ensure safe and effective management of such patients. Case Presentation: A 67-year-old male with a history of symptomatic bradycardia presented with episodes of severe sinus bradycardia at 40 bpm, sinus pauses lasting up to 2.9 seconds, and isolated ventricular extrasystoles, as documented on a two-month Holter monitor. He was admitted to hospital following a nocturnal syncopal episode and an electrocardiogram (ECG) showing a heart rate of 20 bpm. During initial management, there was difficulty obtaining venous access and advancing a temporary pacemaker lead via the jugular vein. As a result, a temporary pacemaker was implanted via the right femoral vein, and the patient was evaluated for permanent pacemaker implantation. Decision-Making: During the procedure in the cardiac catheterisation laboratory, difficulties were encountered in advancing the guidewire towards the subclavian vein. Consequently, bilateral subclavian vein angiography was performed, which revealed a persistent left superior vena cava with anomalous drainage into the coronary sinus. The procedure was therefore deferred. A cardiac CT angiogram confirmed the diagnosis. The cardiothoracic surgery team was subsequently consulted, and an epicardial pacemaker was successfully implanted via a subxiphoid approach in DDDR mode. Conclusion: Persistent left superior vena cava is a rare venous anomaly that can pose significant technical challenges during pacemaker implantation, particularly in patients with atrioventricular block. A thorough pre-procedural assessment of venous anatomy is essential for selecting the most appropriate implantation strategy and minimising procedural risks.