The objective of this post approval registry is to confirm the long-term safety and effectiveness of the Corox Over-the-wire (OTW) Steroid Left Ventricular (LV) lead as used in conjunction with a BIOTRONK cardiac resynchronization therapy defibrillator (CRT-D). The Corox OTW Steroid LV Lead is capable of providing permanent pacing therapy to the left ventricle in a CRT-D system. The following are the specific objectives to be evaluated during this post-approval registry: