Comparison of real time three-dimensional echocardiography and triplane tissue Doppler imaging in the assessment of left ventricular dyssynchrony

Purpose. To compare left ventricular (LV) systolic dyssynchrony indexes derived from real-time three-dimensional echocardiography (3DE) and parameters derived from triplane tissue Doppler imaging (3TDI) in assessing patients with poor LV function and wide QRS complex before and after cardiac resynchronization therapy (CRT). Methods. Thirty-seven patients with dilated cardiomyopathy and wide QRS complex (LV ejection fraction ≤35%, QRS ≥120ms) were studied with 3DE and 3TDI (Vivid 9 ultrasound system, GE, Horten, Norway). Semiautomated LV endocardial border tracking was used to measure systolic dyssynchrony index (SDI) as standard deviation of time-to-minimum systolic volume of the 16 LV segments expressed in percentage of R-R duration. Intraventricular dyssynchrony was determined by 3TDI as the difference between the longest and shortest electromechanical coupling times in LV segments and interventricular dyssynchrony as the difference between electromechanical coupling times in the basal-lateral RV segment and the most delayed LV segment. Results. At six months follow-up after implantation, LV ejection fraction by 3DE improved from 20.6±7.1% to 29.9±12.3%. Interventricular dyssynchrony by triplane TDI was reduced from 76.3±31ms to 29.9±21.8ms (p< 0.005) and intraventricular dyssynchrony from 78±22.3ms to 29.1±10.9ms (p< 0.001). SDI by 3DE was reduced from 18.1±2.8% to 6.9±2.3% (p< 0.001). 3TDI and 3DE parameters had optimal predictive accuracy of the effects of CRT on LV function and a larger area under the receiver operating characteristic curve than the QRS duration. Overall agreement between 3TDI and 3DE was 91% (k= 0.71). Conclusions. 3DE and 3TDI dyssynchrony measurements have acceptable observer variability and values are comparable in pts with heart failure and broad QRS.