title: Assessment of left ventricular mechanical dyssynchrony using real time three-dimensional echocardiography: a comparative study to Doppler tissue imaging.
abstract: OBJECTIVE
  To assess left ventricular mechanical dyssynchrony (LVMD) using real time three-dimensional echocardiography (RT3DE) and comparing it with the different dyssynchrony indices derived from Doppler tissue imaging (DTI) for the same patient.
  
  
  METHODS
  The study included 60 consecutive patients who were considered candidates for CRT, i.e., having ejection fraction ≤35%, NYHA class III or ambulatory class IV, QRS duration ≥120 msec, on optimal pharmacological therapy. Apical RT3DE full volumes were obtained and analyzed to generate the systolic dyssynchrony index (SDI-16), which is the standard deviation of the time to minimal systolic volume of the 16 segments of LV. Color-coded DTI was performed for the three standard apical views with estimation of the mechanical dyssynchrony index (12 Ts-SD), which is the standard deviation of the time to peak systolic velocity at 12 segments of LV.
  
  
  RESULTS
  SDI-16 was 10.96 ± 3.9% (cutoff value: 8.3%), while Ts-SD was 38 ± 10.2 msec (cutoff value: 32.6 msec). The concordance rate for both indices was 75%; however, there was no correlation between both indices (r = 0.14, P = 0.3). SDI-16 showed good correlation with QRS duration (r = 0.45, P < 0.001) and inverse correlation with left ventricular ejection fraction (LVEF) calculated by RT3DE (r =-0.37, P = 0.004), while 12 Ts-SD index showed no correlation with QRS duration (r =-0.0082, P = 0.51) or 2D LVEF (r =-0.26, P = 0.84).
  
  
  CONCLUSIONS
  RT3DE can quantify LVMD by providing the SDI-16 and it may prove to be more useful than DTI as it shows increasing dyssynchrony with increased QRS duration and decreased LVEF.
authors: Cardiology Department, Ain Shams University, Cairo, Egypt. raniasamir_3@msn.com
authors: Rania
authors: R
authors: Samir
authors: Mazen
authors: M
authors: Tawfik
authors: Ahmed M
authors: AM
authors: El Missiri
authors: Ghada
authors: G
authors: El Shahid
authors: Mervat Aboul
authors: MA
authors: Maaty
authors: Maiy
authors: M
authors: El Sayed
mesh_terms: D000704:Analysis of Variance; D015150:Echocardiography, Doppler / Q000379:methods*; D018618:Echocardiography, Doppler, Color / Q000379:methods; D019560:Echocardiography, Three-Dimensional / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*