title: Relation of torsion and myocardial strains to LV ejection fraction in hypertension.
abstract: OBJECTIVE
  The goal of this study was to define the mechanism of preserved ejection fraction (EF) despite depressed myocardial strains in hypertension (HTN).
  
  
  BACKGROUND
  Concentric left ventricular (LV) remodeling in HTN may have normal or supranormal EF despite depressed myocardial strains. The reason for such discordance is not clear. The aim of this study was to comprehensively evaluate the LV mechanics in a well-defined HTN population to define underlying reasons for such a paradox.
  
  
  METHODS
  Sixty-seven patients with resistant HTN and 45 healthy control subjects were studied by cardiac magnetic resonance imaging and tissue tagging with 3-dimensional analysis. Amplitude and directional vector of longitudinal (Ell), circumferential (Ecc), and principal strain for maximal shortening (E3) were computed at basal, mid, and distal LV levels, respectively. LV torsion, defined as the rotation angle of apex relative to base, and LV twist, which accounts for the effects of differential LV remodeling on torsion for comparison among the 2 groups, were also calculated.
  
  
  RESULTS
  LV mass index and LV mass/LV end-diastolic volume ratio were significantly higher in the HTN group compared with controls, consistent with concentric LV remodeling. Ell and Ecc were significantly decreased in amplitude with altered directional vector in HTN compared with controls. However, the amplitude of E3 was similar in the 2 groups. Torsion and twist were significantly higher in HTN, which was mainly due to increase in apical rotation. The HTN group demonstrated significantly increased LV wall thickening compared with controls that resulted in greater LVEF in the HTN group compared with controls (70% vs. 65%, p < 0.001, respectively).
  
  
  CONCLUSIONS
  In compensated LV remodeling secondary to HTN, there is increased LV wall thickening with preserved E3 and increased torsion compared with normal controls. This, therefore, contributes to supranormal LVEF in HTN despite depressed longitudinal and circumferential strains.
authors.affiliation: Division of Cardiovascular Medicine, Department of Medicine, University of Alabama at Birmingham, 1530 3rd Avenue South, Birmingham, AL 35294, USA.
authors.forename: Mustafa I
authors.initials: MI
authors.lastname: Ahmed
authors.forename: Ravi V
authors.initials: RV
authors.lastname: Desai
authors.forename: Krishna K
authors.initials: KK
authors.lastname: Gaddam
authors.forename: Bharath A
authors.initials: BA
authors.lastname: Venkatesh
authors.forename: Shilpi
authors.initials: S
authors.lastname: Agarwal
authors.forename: Seidu
authors.initials: S
authors.lastname: Inusah
authors.forename: Steven G
authors.initials: SG
authors.lastname: Lloyd
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Denney
authors.forename: David
authors.initials: D
authors.lastname: Calhoun
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Dell'italia
authors.forename: Himanshu
authors.initials: H
authors.lastname: Gupta
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D000368:Aged; D000407:Alabama; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D004351:Drug Resistance; D005260:Female; D006801:Humans; D006973:Hypertension / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology*; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009200:Myocardial Contraction; D011446:Prospective Studies; D013318:Stroke Volume; D054159:Torsion, Mechanical; D016277:Ventricular Function, Left; D020257:Ventricular Remodeling
chemical_list: D000959:Antihypertensive Agents