Persistent left-sided superior vena cava (PLSVC) is a central venous anomaly in up to 0.5% of the population. It is usually asymptomatic due to drainage into the right atrium via the coronary sinus. This case report describes placement of a dialysis catheter in a 55-year-old patient with PLSVC and subsequent complications following the uncertainty of the placement. In 10%, PLSVC drains to the left atrium inducing risk of left-to-right shunt and fatal paradoxical emboli in case of catheterisation. Hence, clarification of the central venous haemodynamics by relevant imaging modalities is advised, if suspicion arises.