title: Improvement of left ventricular myocardial short-axis, but not long-axis function or torsion after cardiac resynchronisation therapy: an assessment by two-dimensional speckle tracking.
abstract: OBJECTIVE
  To evaluate whether short-axis function plays a part in determining left ventricular (LV) geometric and functional improvement after cardiac resynchronisation therapy (CRT).
  
  
  RESULTS
  39 patients who received CRT were enrolled. 2D speckle tracking echocardiography was performed at baseline and three months after CRT to assess mean systolic circumferential (epsilon-circum), radial (epsilon-radial) and longitudinal (epsilon-long) strain and torsion. Responders of reverse remodelling (n = 21) had higher baseline mean epsilon-circum than non-responders (p<0.05), who also had improvement in mean epsilon-circum and mean epsilon-radial (both p<0.05) after CRT. Also, the increase in mean epsilon-circum correlated with increase in ejection fraction (r = 0.57, p<0.001) and decrease in mid-cavity width (r = -0.52, p = 0.001). A baseline mean epsilon-circum of >or=6.5% predicted a gain in ejection fraction >or=5%, with a sensitivity of 73% and a specificity of 71%. The baseline epsilon-long was not different between the two groups, and remained unchanged after CRT. The torsion did not improve in responders, but was worsened in non-responders (p<0.05).
  
  
  CONCLUSIONS
  The improvement of LV short-axis function but not long-axis function or torsion contributes to the improvement in LV global function and geometry at three-month follow up. A relatively preserved mean epsilon-circum of >or=6.5% might be useful to predict favourable responses after CRT.
authors.affiliation: Department of Medicine and Therapeutics, Division of Cardiology, Institute of Vascular Medicine, SH Ho Cardiovascular and Stroke Centre, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, NT, Hong Kong.
authors.forename: Q
authors.initials: Q
authors.lastname: Zhang
authors.forename: J W-H
authors.initials: JW
authors.lastname: Fung
authors.forename: G W K
authors.initials: GW
authors.lastname: Yip
authors.forename: J Y-S
authors.initials: JY
authors.lastname: Chan
authors.forename: A P-W
authors.initials: AP
authors.lastname: Lee
authors.forename: Y-Y
authors.initials: YY
authors.lastname: Lam
authors.forename: L-W
authors.initials: LW
authors.lastname: Wu
authors.forename: E B
authors.initials: EB
authors.lastname: Wu
authors.forename: C-M
authors.initials: CM
authors.lastname: Yu
mesh_terms: D016022:Case-Control Studies; D004452:Echocardiography; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy; D020257:Ventricular Remodeling / Q000502:physiology*