Objectives Tissue synchronization imaging (TSI) is a new technique to assess left ventricular (LV) dyssynchrony. The value of TSI to assess LV dyssynchrony automatically was compared directly to manual assessment of LV dyssynchrony from color-coded tissue Doppler imaging (TDI). In addition, the value of TSI to predict response to cardiac resynchronization therapy (CRT) was evaluated.
Methods Sixty symptomatic heart failure patients with depressed LV ejection fraction (LVEF) and QRS >120 ms were evaluated clinically and echocardiographically at baseline and after 6 months of CRT. LV dyssynchrony was measured manually using velocity tracings from the color-coded TDI and automatically using TSI. LV volumes and LVEF were assessed from 2D echocardiography. Clinical responders had to exhibit an improvement in NYHA functional class by >=1 score and an improvement by >=25% in 6-min walking distance after 6 months. Reverse LV remodeling was defined as a reduction of >=15% LV end-systolic volume.
Results There was an excellent correlation between LV dyssynchrony measured manually and automatically derived by TSI (r=0.95, p<0.0001). Thirty-four patients showed clinical response after 6 months of CRT and thirty-two patients showed reverse remodeling. Baseline characteristics were comparable between responders and non-responders, except for more extensive LV dyssynchrony in the responders: 78(26) ms vs 29(29) ms (p<0.0001) as assessed manually, and 79(29) ms vs 28(27) ms (p<0.0001) as assessed with TSI. Using a cutoff value of 65 ms to define extensive LV dyssynchrony, TSI had sensitivity of 81% with a specificity of 89% to predict reverse LV remodeling.
Conclusion TSI allows automatic and reliable assessment of LV dyssynchrony and predicts reverse LV remodeling after CRT.
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