title: Insights into the evolution of myocardial dysfunction in the functionally single right ventricle between staged palliations using speckle-tracking echocardiography.
abstract: BACKGROUND
  The long-term prognosis of hypoplastic left heart syndrome is limited by progressive right ventricular dysfunction. The aim of this study was to determine the trends in single right ventricular systolic function between staged palliative surgeries using speckle-tracking and conventional echocardiography.
  
  
  METHODS
  There were 76 patients with functionally single right ventricles at the (1) pre-Norwood (n = 26), (2) pre-bidirectional cavopulmonary anastomosis (BCPA; n = 19), (3) pre-Fontan (n = 16), and (4) post-Fontan (n = 15) stages, compared with 30 controls of similar ages. Speckle-tracking-derived longitudinal and circumferential strain and strain rate, postsystolic strain index, and mechanical dyssynchrony index were compared with conventional measures of ventricular function. Differences between stages were analyzed using analysis of variance (P < .05).
  
  
  RESULTS
  Strain rate was highest at the pre-Norwood stage and decreased at the other stages (longitudinal P < .0001, circumferential P = .0002), as opposed to controls, in whom strain rate was maintained. Longitudinal strain was significantly decreased at the pre-BCPA stage compared with the pre-Norwood stage (P = .004), but circumferential strain was maintained, resulting in a corresponding decrease in the ratio of longitudinal to circumferential strain, which failed to resemble that of controls. Longitudinal (P = .003) and circumferential (P = .002) postsystolic strain indices were greatest at the pre-BCPA stage.
  
  
  CONCLUSIONS
  A decline in contractility occurred at the pre-BCPA stage. Although there was evidence of adaptation of the single right ventricle, this failed to resemble the normal left ventricle and may be insufficient to handle the chronic volume load or insult from previous surgery. These findings suggest an intrinsic inability of the single right ventricular myocardium to fully adapt to chronic systemic pressures.
authors.affiliation: Stollery Children's Hospital, Edmonton, Alberta, Canada. Electronic address: etham@ualberta.ca.
authors.forename: Edythe B
authors.initials: EB
authors.lastname: Tham
authors.affiliation: Stollery Children's Hospital, Edmonton, Alberta, Canada.
authors.forename: Jeffery F
authors.initials: JF
authors.lastname: Smallhorn
authors.affiliation: Stollery Children's Hospital, Edmonton, Alberta, Canada.
authors.forename: Sachie
authors.initials: S
authors.lastname: Kaneko
authors.affiliation: Stollery Children's Hospital, Edmonton, Alberta, Canada.
authors.forename: Sabira
authors.initials: S
authors.lastname: Valiani
authors.affiliation: Alberta Children's Hospital, Calgary, Alberta, Canada.
authors.forename: Kimberley A
authors.initials: KA
authors.lastname: Myers
authors.affiliation: Stollery Children's Hospital, Edmonton, Alberta, Canada.
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Colen
authors.affiliation: University of Nebraska College of Medicine/Children's Hospital and Medical Center, Omaha, Nebraska.
authors.forename: Shelby
authors.initials: S
authors.lastname: Kutty
authors.affiliation: Stollery Children's Hospital, Edmonton, Alberta, Canada.
authors.forename: Nee S
authors.initials: NS
authors.lastname: Khoo
mesh_terms: D002675:Child, Preschool; D004452:Echocardiography / Q000379:methods*; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D018636:Hypoplastic Left Heart Syndrome / Q000000981:diagnostic imaging* / Q000601:surgery*; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D010166:Palliative Care / Q000379:methods*; D011446:Prospective Studies; D019651:Plastic Surgery Procedures / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D018497:Ventricular Dysfunction, Right / Q000000981:diagnostic imaging* / Q000517:prevention & control*
keywords: Echocardiography; Single ventricle; Speckle-tracking imaging; Strain; Ventricular function