Left ventricular systolic dyssynchrony index by three-dimensional echocardiography in patients with decreased left ventricular function: comparison with tissue Doppler echocardiography.

BACKGROUND

Three-dimensional echocardiography (3DE) can simultaneously assess left ventricular (LV) regional systolic motion and global LV mechanical dyssynchrony.

METHODS

We used 3DE to measure systolic dyssynchrony index (SDI) (standard deviation of the time from cardiac cycle onset to minimum systolic volume in 17 LV segments) in 100 patients and analyzed the association of SDI with other parameters for LV systolic function or dyssynchrony. Eighteen patients who underwent cardiac resynchronization therapy (CRT) were also evaluated at 6 months after CRT, and the association of baseline SDI and tissue Doppler imaging (TDI) dyssynchrony index (Ts-SD) with the change of LV end-systolic volume (ESV) analyzed. Ts-SD was calculated using the standard deviation of the time from the QRS complex to peak systolic velocity.

RESULTS

There was a significant inverse correlation between LVEF and SDI (r =-0.686, P < 0.0001). QRS duration was also significantly correlated to SDI (r = 0.407, P < 0.0001). There was a significant positive correlation between baseline SDI and the decrease in LVESV after CRT (r = 0.42). Baseline SDI was significantly greater in responders (10 patients) than in nonresponders (16.4 ± 5.1 vs. 7.9 ± 2.4%, P < 0.01), but there was no significant difference in Ts-SD. SDI > 11.9% predicted CRT response with a sensitivity of 90% and a specificity of 75%.

CONCLUSIONS

SDI derived from 3DE is a useful parameter to assess global LV systolic dyssynchrony and predict responses to CRT.