title: Comparison of three-dimensional echocardiographic software packages for assessment of left ventricular mechanical dyssynchrony and prediction of response to cardiac resynchronization therapy.
abstract: OBJECTIVE
  We directly compared TomTec and QLAB software packages for the three-dimensional echocardiographic (3DE) assessment of left ventricular (LV) dyssynchrony including their ability to predict response to cardiac resynchronization therapy (CRT) in patients with ischaemic and non-ischaemic cardiomyopathy.
  
  
  RESULTS
  A total of 140 heart failure patients with the LVEF ≤35% and 60 healthy volunteers underwent 3DE. A subgroup of 60 patients underwent CRT and were evaluated before and 6-12 months after implantation. The systolic dyssynchrony index (SDI) was derived from the dispersion of time to minimum regional volume for all 16 LV segments and measured with both software packages and compared using Pearson's correlation and Bland-Altman analysis. Measurements of SDI were significantly higher using TomTec compared with QLAB in both patients (10.9 ± 3.8 vs. 9.7 ± 3.9, P < 0.001) and healthy volunteers (4.1 ± 0.8 vs. 2.4 ± 1, P < 0.001), with large biases and wide limits of agreement. A moderate correlation (r = 0.65, P < 0.001) was observed between both software packages in patients while their inter-observer and intra-observer reliability were good. Of the 60 patients undergoing CRT, reverse remodelling as a measure of response was observed in 41 patients (68%). The optimal SDI cut-off value to predict response to CRT was higher for TomTec than for QLAB (8.8 vs.7.3%, P < 0.001) and demonstrated better sensitivity and specificity (93 and 61%, respectively) compared with QLAB (88 and 33%, respectively). Response prediction in patients with non-ischaemic cardiomyopathy was excellent with a sensitivity and specificity of 95 and 100% for TomTec and 70 and 83% for QLAB using similar cut-off values of 9.1 and 9.2%, respectively.
  
  
  CONCLUSIONS
  Different 3DE software packages for the assessment of mechanical dyssynchrony should not be used interchangeably until better software standardization is achieved. Dyssynchrony assessment with 3DE for the prediction of response to CRT seems particularly useful in patients with non-ischaemic cardiomyopathy.
authors.affiliation: Department of Cardiology 5F 003, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, De Boelelaan 1117, Amsterdam, The Netherlands. mfathy3@yahoo.com
authors.forename: Mohamed F A
authors.initials: MF
authors.lastname: Aly
authors.forename: Sebastiaan A
authors.initials: SA
authors.lastname: Kleijn
authors.forename: Karin
authors.initials: K
authors.lastname: de Boer
authors.forename: Yasser A
authors.initials: YA
authors.lastname: Abd El-Hady
authors.forename: Khalid A
authors.initials: KA
authors.lastname: Sorour
authors.forename: Hossam I
authors.initials: HI
authors.lastname: Kandil
authors.forename: Albert C
authors.initials: AC
authors.lastname: van Rossum
authors.forename: Otto
authors.initials: O
authors.lastname: Kamp
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D016022:Case-Control Studies; D015331:Cohort Studies; D019560:Echocardiography, Three-Dimensional / Q000295:instrumentation* / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000628:therapy; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging / Q000628:therapy; D011237:Predictive Value of Tests; D012016:Reference Values; D015203:Reproducibility of Results; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D012984:Software; D013318:Stroke Volume; D013599:Systole; D013997:Time Factors; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000628:therapy*; D020257:Ventricular Remodeling / Q000502:physiology
keywords: Cardiac resynchronization therapy; Dyssynchrony; Software packages; Three-dimensional echocardiography