Pacemaker Implantation in Persistent Left-Sided Superior Vena Cava

Persistent left-sided superior vena cava (PLSVC) is a rare congenital venous anomaly that may make cardiac device implantation challenging, particularly when implanting cardiac resynchronization therapy (CRT) devices. This anomaly is often recognized incidentally intraoperatively and may significantly influence the procedural strategy and outcomes. We present a case series of 3 patients who underwent permanent pacemaker implantation in whom PLSVC was unexpectedly present. The first case involved a patient with PLSVC and absent right superior vena cava (SVC) in whom a dual-chamber pacemaker was successfully implanted from the right side via the left SVC. The second case involved a CRT implantation in a patient with severe left ventricular systolic dysfunction, aneurysmal PLSVC, and a coronary sinus that precluded lead placement necessitating a change in strategy to conduction system pacing from the right side. The third case involved a patient with dilated cardiomyopathy in whom successful CRT implantation was achieved through the left SVC using modified catheters and guide techniques. In conclusion, persistent left-sided SVC sometimes presents a unique technical challenge during pacemaker implantation. Successful procedural outcome depends on early recognition, flexible procedural planning, and familiarity with alternative venous access and pacing strategies.