title: Delayed and decreased LV untwist and unstrain rate in mutation carriers for hypertrophic cardiomyopathy.
abstract: BACKGROUND
  The echocardiographic focus to detect abnormalities in genetically hypertrophic cardiomyopathy (HCM) affected subjects without left ventricular (LV) hypertrophy (G+/LVH-) has been on diastolic abnormalities in transmitral flow and longitudinal myocardial function with tissue Doppler imaging. The aim of this study was to assess diastolic LV unstrain and untwist.
  
  
  RESULTS
  Forty-one consecutive genotyped family members of HCM patients (mean age 37 ± 11 years, 16 men) and 41 age- and gender-matched healthy volunteers underwent speckle-tracking echocardiography to measure untwist and unstrain. No significant differences between G+/LVH- and control subjects were seen in maximal systolic twist and global longitudinal strain. In diastole, the early peak untwist rate was significantly lower in G+/LVH- subjects compared with control subjects (62 ± 19°s - 1 vs. 76 ± 30°s - 1, P <0.05), whereas the late peak untwist rate tended to be higher. Untwist from maximal twist until the first 20% of diastole was delayed in G+/LVH- subjects (39.3 ± 12.9% vs. 51.3 ± 15.6%, P <0.005). Late diastolic unstrain rate was significantly higher in G+/LVH- subjects in the inferoseptal wall (111 ± 33 s - 1 vs. 94 ± 32 s - 1, P = 0.024), the inferolateral wall (105 ± 42 vs. 75 ± 35 s - 1, P = 0.007) and the anteroseptal wall (97 ± 26 vs. 80 ± 23 s - 1, P = 0.010). Unstrain from maximal twist until the first 20% of diastole was delayed in G+/LVH- subjects in the inferoseptal (18.9 ± 14.0% vs. 30.1 ± 17.7%, P = 0.005), inferolateral (27.1 ± 16.3% vs. 39.2 ± 18.0%, P = 0.015) and anteroseptal (19.1 ± 14.7% vs. 35.8 ± 18.5%, P = 0.0003) segments.
  
  
  CONCLUSIONS
  In mutation carriers, for HCM LV, untwist and unstrain are delayed and untwist rate and unstrain rate are decreased.
authors.affiliation: Department of Cardiology, The Thoraxcenter, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Floris
authors.initials: F
authors.lastname: Kauer
authors.affiliation: Department of Cardiology, The Thoraxcenter, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Bas M
authors.initials: BM
authors.lastname: van Dalen
authors.affiliation: Department of Cardiology, The Thoraxcenter, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Michelle
authors.initials: M
authors.lastname: Michels
authors.affiliation: Department of Cardiology, The Thoraxcenter, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Arend F L
authors.initials: AF
authors.lastname: Schinkel
authors.affiliation: Department of Cardiology, The Thoraxcenter, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Wim B
authors.initials: WB
authors.lastname: Vletter
authors.affiliation: Department of Genetics, The Thoraxcenter, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Marjon
authors.initials: M
authors.lastname: van Slegtenhorst
authors.affiliation: Department of Cardiology, The Thoraxcenter, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Osama I I
authors.initials: OI
authors.lastname: Soliman
authors.affiliation: Department of Cardiology, The Thoraxcenter, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Marcel L
authors.initials: ML
authors.lastname: Geleijnse
mesh_terms: D000328:Adult; D009202:Cardiomyopathies / Q000000981:diagnostic imaging* / Q000235:genetics*; D004198:Disease Susceptibility; D004452:Echocardiography / Q000379:methods*; D005260:Female; D006579:Heterozygote; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D012016:Reference Values; D012720:Severity of Illness Index
keywords: diagnosis; genetics; hypertrophic cardiomyopathy; speckle-tracking echocardiography