title: Increased left ventricular torsion in hypertrophic cardiomyopathy mutation carriers with normal wall thickness.
abstract: BACKGROUND
  Increased left ventricular (LV) torsion has been observed in patients with manifest familial hypertrophic cardiomyopathy (HCM), and is thought to be caused by subendocardial dysfunction. We hypothesize that increased LV torsion is already present in healthy mutation carriers with normal wall thickness.
  
  
  METHODS
  Seventeen carriers with an LV wall thickness <10 mm, and seventeen age and gender matched controls had cardiovascular magnetic resonance (CMR) cine imaging and tissue tagging. LV volumes and mass were calculated from the cine images. LV torsion, torsion rate, endocardial circumferential strain and torsion-to-endocardial-circumferential-shortening (TECS) ratio, which reflects the transmural distribution in contractile function, were determined using tissue tagging.
  
  
  RESULTS
  LV volumes, mass and circumferential strain were comparable between groups, whereas LV ejection fraction, torsion and TECS-ratio were increased in carriers compared to controls (63 ± 3% vs. 60 ± 3%, p = 0.04, 10.1 ± 2.5° vs. 7.7 ± 1.2°, p = 0.001, and 0.52 ± 0.14°/% vs. 0.42 ± 0.10°/%, p = 0.02, respectively).
  
  
  CONCLUSIONS
  Carriers with normal wall thickness display increased LV torsion and TECS-ratio with respect to controls, which might be due to subendocardial myocardial dysfunction. As similar abnormalities are observed in patients with manifest HCM, the changes in healthy carriers may be target for clinical intervention to delay or prevent the onset of hypertrophy.
authors.affiliation: Department of Clinical Physics, Hagaziekenhuis, The Hague, The Netherlands. i.russel@hagaziekenhuis.nl
authors.forename: Iris K
authors.initials: IK
authors.lastname: Rüssel
authors.forename: Wessel P
authors.initials: WP
authors.lastname: Brouwer
authors.forename: Tjeerd
authors.initials: T
authors.lastname: Germans
authors.forename: Paul
authors.initials: P
authors.lastname: Knaapen
authors.forename: J Tim
authors.initials: JT
authors.lastname: Marcus
authors.forename: Jolanda
authors.initials: J
authors.lastname: van der Velden
authors.forename: Marco J W
authors.initials: MJ
authors.lastname: Götte
authors.forename: Albert C
authors.initials: AC
authors.lastname: van Rossum
mesh_terms: D000328:Adult; D024741:Cardiomyopathy, Hypertrophic, Familial / Q000235:genetics / Q000473:pathology / Q000503:physiopathology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009200:Myocardial Contraction / Q000235:genetics; D009426:Netherlands; D014102:Torsion Abnormality / Q000235:genetics / Q000473:pathology / Q000503:physiopathology*; D018487:Ventricular Dysfunction, Left / Q000235:genetics / Q000473:pathology / Q000503:physiopathology*; D016277:Ventricular Function, Left / Q000235:genetics