title: Three-dimensional mechanical dyssynchrony and myocardial deformation of the left ventricle in patients with tricuspid atresia after Fontan procedure.
abstract: BACKGROUND
  The aim of this study was to test the hypothesis that dyssynchronous contraction of functional single ventricles occurs in Fontan patients and is related to indices of myocardial deformation and global ventricular function.
  
  
  METHODS
  Twenty patients with tricuspid atresia (mean age, 23.5 ± 7.1 years) were studied 17.8 ± 3.8 years after undergoing the Fontan procedure. Three-dimensional echocardiographic data were acquired for determination of left ventricular (LV) volumes and systolic dyssynchrony indices. LV myocardial deformation was determined using speckle-tracking echocardiography. Calibrated integrated backscatter intensity was measured as an index of myocardial fibrosis. The results were compared with those in 20 controls.
  
  
  RESULTS
  Compared with controls, patients had significantly greater systolic dyssynchrony indices (6.13 ± 1.32% vs 4.06 ± 0.84%, P < .001). The prevalence of LV mechanical dyssynchrony (systolic dyssynchrony index > 5.74%) in patients was 55% (95% confidence interval, 32%-77%). LV global systolic longitudinal, radial, and circumferential strain (P < .001 for all), longitudinal systolic (P < .001) and early diastolic (P < .001) strain rate, and circumferential systolic (P < .001) and early diastolic (P = .009) strain rate were significantly lower in patients than in controls, while the average calibrated integrated backscatter was higher (P < .001). Patients with LV dyssynchrony (n = 11) had lower global LV longitudinal strain (P = .02), reduced LV ejection fractions (P = .002), and higher average calibrated integrated backscatter (P = .03) compared with those without LV dyssynchrony (n = 9).
  
  
  CONCLUSIONS
  A high proportion of patients with tricuspid atresia after the Fontan operation exhibit LV mechanical dyssynchrony, which may in part be related to myocardial fibrosis and has implications for myocardial deformation and global ventricular function.
authors.affiliation: Division of Paediatric Cardiology, Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital, University of Hong Kong, 102 Pokfulam Road, Hong Kong, China.
authors.forename: Po-Ki
authors.initials: PK
authors.lastname: Ho
authors.forename: Clare T M
authors.initials: CT
authors.lastname: Lai
authors.forename: Sophia J
authors.initials: SJ
authors.lastname: Wong
authors.forename: Yiu-Fai
authors.initials: YF
authors.lastname: Cheung
mesh_terms: D000328:Adult; D004452:Echocardiography / Q000379:methods; D019560:Echocardiography, Three-Dimensional; D005260:Female; D018729:Fontan Procedure; D006352:Heart Ventricles / Q000002:abnormalities; D006801:Humans; D008297:Male; D009200:Myocardial Contraction / Q000502:physiology*; D011184:Postoperative Period; D013318:Stroke Volume; D018785:Tricuspid Atresia / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology*; D055815:Young Adult