title: Impact of left ventricular size on tissue Doppler and longitudinal strain by speckle tracking for assessing wall motion and mechanical dyssynchrony in candidates for cardiac resynchronization therapy.
abstract: BACKGROUND
  Myocardial dysfunction and left ventricular (LV) geometry deformation may reduce the accuracy of tissue Doppler imaging (TDI) in assessing myocardial contractility.
  
  
  METHODS
  In 92 patients with heart failure who underwent cardiac resynchronization therapy (CRT), we assessed the impact of LV end-diastolic volume on the accuracy of peak longitudinal velocity (TDI) and strain (epsilon(L) by speckle tracking) to assess regional wall motion and LV dyssynchrony.
  
  
  RESULTS
  Peak-epsilon correlated to normal (-13% +/- 6%, n = 259), hypokinetic (-10% +/- 5%, n = 347), and akinetic (-7% +/- 5%, n = 498, P < .0001) wall motion independent of LV size. In contrast, velocity failed to distinguish normal from dysfunctional segments in patients with severe LV dilatation (end-diastolic volume > 250 mL). The 12 standard deviation of time to peak systolic velocity and the opposing septal-lateral wall delay by strain and TDI failed to predict response to CRT, whereas the 12 segment standard deviation of time to peak epsilon correlated to end-systolic volume reduction (r = -0.39, P < .001).
  
  
  CONCLUSIONS
  Accuracy of TDI in assessing LV wall regional motion is limited in severely dilated ventricles and probably affects LV dyssynchrony measurement.
authors.affiliation: Department of Cardiovascular Medicine, Heart & Vascular Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
authors.forename: Pascal
authors.initials: P
authors.lastname: Lim
authors.forename: Laurens
authors.initials: L
authors.lastname: Mitchell-Heggs
authors.forename: Adisai
authors.initials: A
authors.lastname: Buakhamsri
authors.forename: James D
authors.initials: JD
authors.lastname: Thomas
authors.forename: Richard A
authors.initials: RA
authors.lastname: Grimm
mesh_terms: D000368:Aged; D000465:Algorithms; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D015150:Echocardiography, Doppler / Q000379:methods*; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012044:Regression Analysis; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012984:Software; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000517:prevention & control*