Changes in global left ventricular function by multidirectional strain assessment in heart failure patients undergoing cardiac resynchronization therapy.

BACKGROUND: The aim of this study was to evaluate the acute and late effects of cardiac resynchronization therapy (CRT) on multidirectional left ventricular (LV) strain assessed by two-dimensional speckle-tracking imaging and automated function imaging (AFI).
METHODS: Multidirectional LV strain (global radial strain [GRS Avg], global circumferential strain [GCS Avg], and global longitudinal peak systolic strain [GLPSS Avg]) were measured in 141 patients with heart failure before CRT implantation, immediately afterward, and after 3 to 6 months of follow-up. Moreover, the acute effects on multidirectional LV strain were evaluated after interrupting CRT at follow-up. Response to CRT was defined as a decrease in LV end-systolic volume > or = 15%.
RESULTS: Responders (57%) and nonresponders (43%) showed similar baseline values for GRS Avg, GCS Avg, and GLPSS Avg. At follow-up, significant improvement in multidirectional LV strain, combined with significant reverse LV remodeling and improvement in LV ejection fraction, was noted only in responders. Importantly, no significant changes in multidirectional LV strain were observed immediately after CRT device implantation or after device interruption at follow-up.
CONCLUSIONS: Two-dimensional speckle-tracking imaging and AFI enable the quantification of multidirectional LV mechanics. Improvement in LV strain in the 3 orthogonal directions after CRT appears to be a long-term effect and is related to the extent of reverse LV remodeling after CRT.