title: Utility of speckle tracking echocardiography to characterize dysfunctional myocardium in patients with ischemic cardiomyopathy referred for cardiac resynchronization therapy.
abstract: BACKGROUND
  Assessment of transmural scar at the site of latest mechanical activation is relevant to maximize outcomes in cardiac resynchronization therapy (CRT). Few studies have assessed the ability of speckle tracking echocardiography (STE)-derived short-axis strain to identify segmental myocardial scar, defined by contrast-enhanced cardiac magnetic resonance imaging (CMR), in patients referred for CRT.
  
  
  METHODS
  A total of 26 patients with ischemic cardiomyopathy who underwent preprocedure echocardiography and CMR were studied. Extent of transmural scar was assessed using contrast-enhanced CMR and corresponding peak segmental radial and circumferential strains were derived using two-dimensional (2D) STE. Total left ventricle (LV) scar volume was compared with parameters of global strain. CRT response was defined as >15% reduction in LV end systolic volume (LVESV) at 6 months.
  
  
  RESULTS
  Speckle tracking short-axis strain analysis was technically possible in over 90% of LV segments. Applying a segmental radial strain cutoff value of 10% distinguished segments with >50% scar area with a high negative predictive value (98%). Global longitudinal strain <-5% predicted CRT response.
  
  
  CONCLUSIONS
  Two-dimensional STE offers potential to characterize dysfunctional myocardium and define segmental scar offering an integrated imaging approach to guide LV lead placement for CRT.
authors.affiliation: Department of Medicine, Addenbrooke's Hospital, University of Cambridge, Hills Road, Cambridge, United Kingdom.
authors.forename: Anna C
authors.initials: AC
authors.lastname: Kydd
authors.forename: Fakhar
authors.initials: F
authors.lastname: Khan
authors.forename: Deepa
authors.initials: D
authors.lastname: Gopalan
authors.forename: Liam
authors.initials: L
authors.lastname: Ring
authors.forename: Bushra S
authors.initials: BS
authors.lastname: Rana
authors.forename: Mohan S
authors.initials: MS
authors.lastname: Virdee
authors.forename: David P
authors.initials: DP
authors.lastname: Dutka
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D009202:Cardiomyopathies / Q000150:complications / Q000000981:diagnostic imaging* / Q000628:therapy*; D002921:Cicatrix / Q000150:complications / Q000000981:diagnostic imaging* / Q000628:therapy; D004452:Echocardiography / Q000379:methods; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000209:etiology / Q000628:therapy; D012017:Referral and Consultation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000209:etiology / Q000517:prevention & control
keywords: cardiac resynchronization therapy; myocardial dysfunction; scar; speckle tracking echocardiography