Cardiac resynchronization therapy in persistent left superior vena cava: Can you do it two-leads-only?

Persistent left superior vena cava (PLSVC) is a congenital developmental abnormality of the sinus venosus with an incidence of 0.47% in patients undergoing cardiac implantable electronic devices.1 The 2 variants include a double superior vena cava (right and left SVC, with or without an innominate vein connecting the two) or a single left-sided SVC (without a right SVC), which may occur in one third of PLSVC subjects.1 This anatomic variant may hinder pacemaker / cardiac resynchronization therapy (CRT) device implantation, especially when the placement of the left ventricular (LV) lead is concerned.