PURPOSE: To image late mechanical activation and identify effective left-ventricular (LV) pacing sites for cardiac resynchronization therapy (CRT). There is variability in defining mechanical activation time, with some studies using the time to peak strain (TPS) and some using the time to @entity3207 ( @entity3207 ). We developed improved methods for imaging mechanical activation and evaluated them in @entity712 ( @entity712 ) @entity1 undergoing CRT. MATERIALS AND METHODS: We applied active contours to cine displacement encoding with stimulated echoes (DENSE) strain images to detect @entity3207 . Six healthy volunteers underwent magnetic resonance imaging (MRI) at 1.5T, and 50 @entity1 underwent pre-CRT MRI (strain, scar, volumes) and echocardiography, assessment of the electrical activation time (Q-LV) at the LV pacing site, and echocardiography assessment of LV reverse remodeling 6 months after CRT. TPS at the LV pacing site was also measured by DENSE. RESULTS: The latest @entity3207 was greater in @entity712 @entity1 vs. healthy subjects (112        28   msec vs. 61        7   msec, P   <   0.01). The correlation between @entity3207 and Q-LV was strong (r   >   0.75; P   <   0.001) and better than between TPS and Q-LV (r   <   0.62; P   >=    0.006). Twenty-three of 50 @entity1 had the latest activating segment in a region other than the mid-ventricular lateral wall, the most common site for the CRT LV lead. Using a multivariable model, @entity3207 /QRS was significantly associated with LV reverse remodeling even after adjustment for overall dyssynchrony and scar (P   <   0.05), whereas TPS was not (P   =   0.49). CONCLUSION: Late activation by cine DENSE @entity3207 analysis is associated with improved LV reverse remodeling with CRT and deserves further study as a tool to achieve optimal LV lead placement in CRT. LEVEL OF EVIDENCE: 1 J. Magn. Reson. Imaging 2017.

Imaging left-ventricular mechanical activation in @entity712 XXXX using cine DENSE MRI: Validation and implications for cardiac resynchronization therapy.

@entity3207 :: ('MESH:C535850', 'Disease') :: ['the onset of circumferential shortening', 'TOS'] @entity1 :: ('9606', 'Species') :: ['patients'] @entity712 :: ('MESH:D006333', 'Disease') :: ['HF', 'heart failure']
@entity1 :: (9606,Species) :: ['patients']
