Implementation of a Protocol Utilizing Adaptive CRT in a Normal AV Conduction, CRT Non-Response Population at Generator Replacement

Inclusion Criteria: * Normal AV conduction (SAV\<220 ms or PAV\<270 MS) * Left Bundle Branch Block (defined as \> or = to 140 ms (male) or \> or = 130 (female), QR or rS in leads V1 and V2, and Mid QRS notching or slurring in v 2 of leads V1, V2, V5, V6 and I and aVL.) * Patient and/or physician assessment or unchanged or worsened heart failure status at the time of recommended replacement time (RRT) for previous CRT device. * Sinus Rhythm at the time of enrollment Exclusion Criteria: * Moderate to severe Aortic Stenosis * Moderate to severe Mitral Regurgitation * Patient age \<18 years old * AF burden \>15% * Severe pulmonary disease requiring supplemental oxygen use * ESRD * System Modification at RRT Generator Changeout * AdaptivCRT prior to enrollment * Expected patient longevity \< 1 year * Persistant or chronic atrial fibriliation * Women who are pregnant or who plan to become pregnant during the clinical trial