Tissue synchronisation imaging accurately measures left ventricular dyssynchrony and predicts response to cardiac resynchronisation therapy

Background: Tissue synchronisation imaging(TSI) is a new technique to assess left ventricular(LV) dyssynchrony. Objectives: The value of using TSI to automatically assess LV dyssynchrony compared with manual assessment of LV dyssynchrony from colour-coded tissue Doppler imaging(TDI), and to evaluate the value of TSI to predict response to cardiac resynchronisation therapy(CRT). Methods: 60 symptomatic patients with heart failure 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 colour-coded TDI and automatically using TSI. LV volumes and LVEF were assessed from two-dimensional echocardiography. Clinical responders had to exhibit an improvement in New York Heart Association functional class by ≥ 1 score and an improvement by ≥ 25% in 6 min walking distance after 6 months. Reverse LV remodelling was defined as a reduction of ≥ 15% LV end-systolic volume. Results: An excellent correlation was observed between LV dyssynchrony measured manually and automatically derived by TSI(r=0.95, p 0.001). 34 patients showed clinical response after 6 months of CRT and 32 patients showed reverse remodelling. Baseline characteristics were comparable between responders and non-responders, except for more extensive LV dyssynchrony in the responders: 78(26) vs 29(29) ms(p 0.001) as assessed manually, and 79(29) vs 28(27) ms(p 0.001) as assessed with TSI. Using a cut-off value of 65 ms to define extensive LV dyssynchrony, TSI had a sensitivity of 81% with a specificity of 89% to predict reverse LV remodelling. Conclusion: TSI allows automatic and reliable assessment of LV dyssynchrony and predicts reverse LV remodelling after CRT.