title: The relationship between time from myocardial infarction, left ventricular dyssynchrony, and the risk for ventricular arrhythmia: speckle-tracking echocardiographic analysis.
abstract: BACKGROUND
  Differences in arrhythmogenic substrate may explain the variable efficacy of implantable cardioverter-defibrillators (ICDs) in primary sudden cardiac death prevention over time after myocardial infarction (MI). Speckle-tracking echocardiography allows the assessment left ventricular (LV) dyssynchrony, which may reflect the electromechanical heterogeneity of myocardial tissue. The aim of the present study was to evaluate the relationship among LV dyssynchrony, age of MI, and their association with the risk for ventricular tachycardia (VT) after MI.
  
  
  METHODS
  A total of 206 patients (median age, 67 years; 87% men) with prior MIs (median MI age, 6.2 years; interquartile range, 0.66-15 years) who underwent programmed electrical stimulation, speckle-tracking echocardiography, and ICD implantation were retrospectively evaluated. LV dyssynchrony was defined as the standard deviation of time to peak longitudinal systolic strain values using speckle-tracking strain echocardiography. LV scar burden was evaluated by the percentage of segments exhibiting scar (defined as an absolute longitudinal strain of magnitude < 4.5%). Patients were followed up for the occurrence of first monomorphic VT requiring ICD therapy (antitachycardia pacing or shock) for a median of 24 months.
  
  
  RESULTS
  In total, 75 individuals experienced the primary end point of monomorphic VT. LV dyssynchrony was independently associated with the occurrence of VT at follow-up (hazard ratio per 10-msec increase, 1.12; 95% confidence interval, 1.07-1.18; P < .001), together with nonrevascularization of the infarct-related artery and VT inducibility. Patients with older (>180 months) MIs had a higher likelihood of VT inducibility (88% vs 63%, P = .003) and greater scar burden (14.7 ± 15.8% vs 10.7 ± 11.4%, P = .03) compared with patients with recent (<8 months) MIs.
  
  
  CONCLUSIONS
  LV dyssynchrony is independently associated with the occurrence of VT after MI.
authors: Disciplines of Medicine, Flinders University and the University of Adelaide, Adelaide, Australia; Population Health Research Institute, McMaster University and Hamilton Health Sciences, Hamilton, Ontario, Canada.
authors: Darryl P
authors: DP
authors: Leong
authors: Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands.
authors: Georgette E
authors: GE
authors: Hoogslag
authors: Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands.
authors: Sebastiaan R D
authors: SR
authors: Piers
authors: Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands.
authors: Ulas
authors: U
authors: Höke
authors: Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands.
authors: Joep
authors: J
authors: Thijssen
authors: Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands.
authors: Nina Ajmone
authors: NA
authors: Marsan
authors: Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands.
authors: Martin J
authors: MJ
authors: Schalij
authors: Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands.
authors: Katja
authors: K
authors: Zeppenfeld
authors: Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands.
authors: Jeroen J
authors: JJ
authors: Bax
authors: Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands. Electronic address: v.delgado@lumc.nl.
authors: Victoria
authors: V
authors: Delgado
mesh_terms: D000368:Aged; D004452:Echocardiography / Q000379:methods*; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000379:methods; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D009203:Myocardial Infarction / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013318:Stroke Volume; D017180:Tachycardia, Ventricular / Q000000981:diagnostic imaging* / Q000209:etiology* / Q000503:physiopathology; D013997:Time Factors; D018487:Ventricular Dysfunction, Left / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology
keywords: Echocardiography; Myocardial infarction; Scar; Strain; Ventricular tachycardia