 CRT results in electromechanical synchrony, leading to an improved ejection fraction, exercise tolerance, and reduction of symptoms. Although electrical re-synchronization and intra-procedural hemodynamic improvement are achieved after the device is implanted, the sustained clinical improvement is likely due to ventricular reverse remodeling. A major issue with CRT is that approximately a third of patients receiving devices do not achieve improved clinical or functional status, and fail to undergo changes in ventricular geometry, and ventricular remodeling. It remains unknown whether this is due to abnormalities in the factors involved in lead placement or procedural strategies, geometric remodeling, alterations in cardiac energy metabolism, supply of energy i.e. coronary blood flow, or inappropriateinadequate microvascular proliferation. 