title: Simple regional strain pattern analysis to predict response to cardiac resynchronization therapy: rationale, initial results, and advantages.
abstract: BACKGROUND
  A classical strain pattern of early contraction in one wall and prestretching of the opposing wall followed by late contraction has previously been associated with left bundle branch block (LBBB) activation and short-term response to cardiac resynchronization therapy (CRT). Aims of this study were to establish the long-term predictive value of an LBBB-related strain pattern and to identify changes in contraction patterns during short-term and long-term CRT.
  
  
  RESULTS
  Sixty-seven patients with standard CRT criteria were prospectively enrolled between early 2009 and late 2010. Echocardiography including regional strain analysis by 2-dimensional speckle tracking was performed 1 week before implantation, at day 1, and 6 months after. Response was defined as a decrease in left ventricular end-systolic volume ≥ 15%. The predictive ability of a classical pattern was compared with time-to-peak measurements from velocity and deformation analysis. Forty-three patients (65%) were classified as responders. The presence of a classical pattern showed 91% specificity and 95% sensitivity for response and performed significantly better than time-to-peak parameters in prediction of response to CRT (P < .001, all). In responders, CRT acutely increased septal longitudinal peak systolic strain (-8.7% ± 3.6% to -11.1% ± 3%, P < .001) but not in nonresponders.
  
  
  CONCLUSIONS
  The classical pattern is highly predictive of response to CRT and superior to time-to-peak methods. Patients who obtain long-term reverse remodeling are characterized by short-term reversal of the classical strain pattern. These findings emphasize the value of recognizing potentially reversible strain patterns in selection of CRT candidates.
authors.affiliation: Department of Cardiology, Gentofte University Hospital, Skejby, Denmark. niels.risum@dm.duke.edu
authors.forename: Niels
authors.initials: N
authors.lastname: Risum
authors.forename: Christian
authors.initials: C
authors.lastname: Jons
authors.forename: Niels T
authors.initials: NT
authors.lastname: Olsen
authors.forename: Thomas
authors.initials: T
authors.lastname: Fritz-Hansen
authors.forename: Niels E
authors.initials: NE
authors.lastname: Bruun
authors.forename: Michael V
authors.initials: MV
authors.lastname: Hojgaard
authors.forename: Nana
authors.initials: N
authors.lastname: Valeur
authors.forename: Mads B
authors.initials: MB
authors.lastname: Kronborg
authors.forename: Joseph
authors.initials: J
authors.lastname: Kisslo
authors.forename: Peter
authors.initials: P
authors.lastname: Sogaard
mesh_terms: D000368:Aged; D002037:Bundle-Branch Block / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy*; D058406:Cardiac Resynchronization Therapy; D004452:Echocardiography / Q000379:methods; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013599:Systole / Q000502:physiology; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000628:therapy; D020257:Ventricular Remodeling / Q000502:physiology