Metabolic Mapping and Cardiac Resynchronization

Inclusion Criteria:

LVEF 35%-50%
NYHA class I-II
QRS duration of ≥120ms
Left bundle branch block (LBBB)
Patient is able to receive a transvenous pectoral CRT implant
Patient is able to sign informed consent
Two echocardiograms are required to confirm a stable reduced LVEF
Patient is on optimal and stable medical therapy (ACE inhibitor or AT1 blocker, beta blocker, etc. over the last 6 months)

Exclusion Criteria:

Advanced comorbid conditions with life expectancy <1 year
Patient is <18 of years of age
Patient has a CRT device
Female patients who is pregnant or not on a reliable form of birth control. Women of childbearing potential are required to have negative pregnancy test within the 7 days prior to device implant
Unwilling or unable to return for required follow-up visits
Patient decides study participation is cost-prohibited