title: Three-Dimensional Left Ventricular Torsion in Patients With Dilated Cardiomyopathy　- A Marker of Disease Severity.
abstract: LV twist has a key role in maintaining left ventricular (LV) contractility during exercise. The purpose of this study was to investigate LV torsion instead of twist as a surrogate marker of peak oxygen uptake (peak V̇O2) assessed by cardiopulmonary exercise testing (CPET) in patients with non-ischemic dilated cardiomyopathy (DCM).
  
  
  
  We evaluated 45 outpatients with DCM (50±12 years, 24% females) with 3D speckle-tracking electrocardiography prior to CPET. LV torsion, LV ejection fraction (EF), LV diastolic function, LV global longitudinal (GLS) and circumferential (GCS) strain were quantified. A reduced functional capacity (FC) was defined as a peak V̇O2<20 mL/kg/min. LV torsion correlated most strongly with peak V̇O2(r=0.76, P<0.001). LV torsion instead of twist was an independent predictor of peak V̇O2(B: 0.59 to 0.71, P<0.001) in multivariable analyses. Impaired LV torsion <0.61 degrees/cm was able to predict a reduced FC with higher sensitivity and specificity (0.91 and 0.81; area under the curve (AUC): 0.88, P<0.001) than LV EF, GLS or GCS (AUC 0.64, 0.63 and 0.66; P<0.05 for differences in AUC).
  
  
  
  Peak V̇O2correlated more strongly with LV torsion than with LV diastolic function, LV EF, GLS or GCS. LV torsion had high accuracy in identifying patients with a reduced FC.
authors.affiliation: Department of Cardiology, University of Technology Dresden.
authors.forename: Krunoslav Michael
authors.initials: KM
authors.lastname: Sveric
authors.forename: Stefan
authors.initials: S
authors.lastname: Ulbrich
authors.forename: Mohamed
authors.initials: M
authors.lastname: Rady
authors.forename: Tobias
authors.initials: T
authors.lastname: Ruf
authors.forename: Heda
authors.initials: H
authors.lastname: Kvakan
authors.forename: Ruth H
authors.initials: RH
authors.lastname: Strasser
authors.forename: Stefanie
authors.initials: S
authors.lastname: Jellinghaus
mesh_terms: D000328:Adult; D019540:Area Under Curve; D002311:Cardiomyopathy, Dilated / Q000503:physiopathology*; D005080:Exercise Test / Q000379:methods; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D054159:Torsion, Mechanical; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology*; D016277:Ventricular Function, Left / Q000502:physiology