The specific required visits for this registry are: Enrollment, Three-month, Six month, One-year, Routine Follow-Ups (every subsequent 6 months), Interim follow-ups for Corox OTW Steroid LV lead related visits, and Out of Service visit. Data will be collected at each patient follow-up. The programmed pacing parameters, LV pacing impedance, and LV pacing threshold measurement at 0.5ms pulse width will be obtained. The programming parameters will be set to best suit each patient. If adequate system function, including effective CRT, cannot be obtained, the patient should not be selected for the registry.