Persistent left superior vena cava and pacemaker implantation.

Our study group read with interest the paper from Vijayvergiya et al describing the implantation of an implantable cardioverter-defibrillator lead in the presence of the persistence of the left superior vena cava. The issue of the identification a persistent left superior vena cava is of paramount importance in interventional cardiology, being the most common venous anomaly of the thoracic distribution, and because it may create some problem to any physician while performing a pacemaker lead implantation. In our letter we underscore the specific issues related to pacemaker implantation while encountering a persistent left superior vena cava (and maybe the absence of the right vena cava) and the workup that should be performed to obtain the preoperative diagnosis of the venous anomaly. More specifically, we consider avoiding any kind of defibrillator lead implantation through the coronary sinus for safety issues, and underscore the straightforward transthoracic ultrasound approach to identify the left superior vena cava.