title: Real-time 3-dimensional echocardiography provides new insight into mechanisms of tricuspid valve regurgitation in patients with hypoplastic left heart syndrome.
abstract: BACKGROUND
  Tricuspid regurgitation in hypoplastic left heart syndrome has an impact on outcome, but its mechanisms remain unclear.
  
  
  RESULTS
  Real-time 3-dimensional echocardiography was performed in 35 patients with hypoplastic left heart syndrome (age, 1 month to 10 years; 10 after first-stage Norwood, 12 after superior cavopulmonary shunt, 13 after Fontan). From the 3-dimensional data set, we marked the annulus in systole and diastole. At mid systole, we marked the location of the papillary muscle tip and point of chordal attachment to the leaflet. We traced the surfaces of the tricuspid valve leaflets and measured the volume of leaflet prolapse, tethering, annular and septal leaflet areas, and papillary muscle position. Seventeen patients had moderate tricuspid regurgitation (prolapse, 7; tethered leaflets, 7) and 18 mild (prolapse, 0; tethered leaflets, 7). Multiple linear regression analysis revealed that moderate tricuspid regurgitation is associated with leaflet tethering and prolapse; that in hypoplastic left heart syndrome with tethered leaflets, the papillary muscle is displaced laterally and the tricuspid annulus is more planar; and that enlargement of the annulus at mid systole, small septal leaflet area, and age affect the degree of prolapse.
  
  
  CONCLUSIONS
  In hypoplastic left heart syndrome, moderate tricuspid regurgitation may be associated with increasing age, geometrical changes of the annulus, leaflet prolapse, lateral papillary muscle displacement, and subsequent leaflet tethering, as well as a smaller septal leaflet.
authors.affiliation: Department of Pediatrics, University of Alberta, Alberta, Canada.
authors.forename: K
authors.initials: K
authors.lastname: Takahashi
authors.forename: A
authors.initials: A
authors.lastname: Inage
authors.forename: I M
authors.initials: IM
authors.lastname: Rebeyka
authors.forename: D B
authors.initials: DB
authors.lastname: Ross
authors.forename: R B
authors.initials: RB
authors.lastname: Thompson
authors.forename: A S
authors.initials: AS
authors.lastname: Mackie
authors.forename: J F
authors.initials: JF
authors.lastname: Smallhorn
mesh_terms: D002648:Child; D002675:Child, Preschool; D019560:Echocardiography, Three-Dimensional / Q000379:methods*; D005260:Female; D006801:Humans; D018636:Hypoplastic Left Heart Syndrome / Q000000981:diagnostic imaging*; D007223:Infant; D008297:Male; D010210:Papillary Muscles / Q000473:pathology; D014262:Tricuspid Valve Insufficiency / Q000000981:diagnostic imaging*; D016278:Ventricular Function, Right