Coronary sinus atresia and persistent left superior vena cava with the presence of thrombus complicating implantation of a left ventricular pacing lead.

A 68-year-old male with heart failure and a suitable candidate for resynchronization therapy was referred to our hospital because of a failed coronary sinus (CS) lead implant. Catheterization of the CS initially also failed in our department but a left coronary angiogram revealed atresia of the CS and drainage of the coronary venous system via a persistent left superior vena cava (PLSVC). Implantation of a CS lead through the PLSVC could be accomplished after a selective angiogram, even in spite of the presence of a large thrombus at the junction of PLSVC and CS.