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