A persistent left superior vena cava (PLSVC) was discovered at the implantation of a cardiac resynchronization system in a woman with an idiopathic dilated cardiomyopathy. Standard leads were used to obtain right ventricular and right atrial (RA) stimulation according to a formerly described technique. The left ventricle was stimulated through the posterolateral vein of the heart by a novel lead design to be used over a guidewire for placement. Despite expected difficulties in this anatomic situation, the research lead was positioned in 23 minutes.