title: Left ventricular discoordination index measured by speckle tracking strain rate imaging predicts reverse remodelling and survival after cardiac resynchronization therapy.
abstract: OBJECTIVE
  This study aimed to evaluate the predictive value of a baseline speckle tracking strain rate imaging-derived discoordination index for response to cardiac resynchronization therapy (CRT).
  
  
  RESULTS
  Ninety-seven patients with QRS ≥120 ms and left ventricular (LV) ejection fraction ≤35% were prospectively followed after CRT in the Mayo CRT Registry. The LV discoordination index (stretch/shortening or thinning/thickening during ejection) was calculated from three types of deformation, radial, circumferential, and longitudinal, using two-dimensional speckle tracking strain rate imaging. The benefit of CRT was evaluated by reverse remodelling (i.e. reduction of LV end-systolic volume ≥15% at 6-month follow-up) and survival. The optimal cut-off value of the baseline discoordination index in discriminating responders from non-responders was determined by receiver operating characteristic curve analysis. Significant differences in baseline indices between responders and non-responders were noted for radial and circumferential discoordination indices. A mid-ventricular radial discoordination index (RDI-M) >38% best predicted responders, especially in patients with ischaemic cardiomyopathy (area under the curve 0.86 for all patients, sensitivity 80%, and specificity 91%). Death occurred in 28 patients over a median follow-up of 3.2 years. When adjusted for confounding variables, lack of significant discoordination (RDI-M <38%) before CRT was associated with a particularly high mortality (hazard ratio 7.05, 95% confidence interval 2.45-26.0).
  
  
  CONCLUSIONS
  LV discoordination assessed by speckle tracking RDI-M imaging was able to predict reverse remodelling at 6 months and survival of patients who received CRT.
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Chun-Li
authors.initials: CL
authors.lastname: Wang
authors.forename: Brian D
authors.initials: BD
authors.lastname: Powell
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Redfield
authors.forename: Chinami
authors.initials: C
authors.lastname: Miyazaki
authors.forename: Nowell M
authors.initials: NM
authors.lastname: Fine
authors.forename: Lyle J
authors.initials: LJ
authors.lastname: Olson
authors.forename: Yong-Mei
authors.initials: YM
authors.lastname: Cha
authors.forename: Raul E
authors.initials: RE
authors.lastname: Espinosa
authors.forename: David L
authors.initials: DL
authors.lastname: Hayes
authors.forename: David O
authors.initials: DO
authors.lastname: Hodge
authors.forename: Grace
authors.initials: G
authors.lastname: Lin
authors.forename: Paul A
authors.initials: PA
authors.lastname: Friedman
authors.forename: Jae K
authors.initials: JK
authors.lastname: Oh
mesh_terms: D058406:Cardiac Resynchronization Therapy / Q000379:methods* / Q000401:mortality; D004452:Echocardiography; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000503:physiopathology / Q000628:therapy*; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D016019:Survival Analysis; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000628:therapy; D020257:Ventricular Remodeling / Q000502:physiology*