Primary Outcome Measures:
- Improvement in LV function and LV remodelling [ Time Frame: 6 to 12 months ]
In a 16 segment model circumferential strain will be used to determine the segment with latest peak systolic circumferential strain prior to CRT, considered as the optimal LV lead target. LV lead will be defined by (1) fluoroscopy, (2) the maximal temporal difference of peak circumferential strain before-to-on CRT and (3) the earliest peak systolic circumferential strain during LV pacing. For all 3 modalities optimal LV lead position is defined as concordance or immediate neighbouring of the segment with defined LV lead position to the determined optimal target segment. At follow-up echocardiography will be performed to determine improvement in LV function and remodeling.