Cardiac resynchronization utilizes left ventricular (LV) pacing through electrodes inserted through the coronary sinus (CS) into LV veins to stimulate the LV myocardium. Successful insertion of LV pacing leads requires an understanding of the anatomic changes associated with cardiac remodeling and a combination of standard pacing and cardiac catheterization and interventional techniques. CS catheterization and venography identify and access the target LV vein for insertion of the pacing lead. Obtaining an adequate lead position involves reaching appropriate capture thresholds, avoiding extra-cardiac stimulation, and stabilizing the lead to avoid dislodgement.