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 > or =1 score and an improvement by > or =25% in 6 min walking distance after 6 months. Reverse LV remodelling was defined as a reduction of > or =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.