title: Left ventricular scar burden specifies the potential for ventricular arrhythmogenesis: an LGE-CMR study.
abstract: BACKGROUND
  The extent of left ventricular (LV) scar, characterized by late gadolinium enhancement cardiac MRI (LGE-CMR), has been shown to predict the occurrence of ventricular arrhythmias in implantable cardioverter defibrillator (ICD) recipients. However, the specificity of LGE-CMR for sudden cardiac death (SCD) versus non-SCD is unclear. The aim of this retrospective, observational study was to evaluate this relationship in a cohort of ICD recipients.
  
  
  RESULTS
  We included consecutive patients who had undergone LGE-CMR before ICD implantation over a 4-year period (2006-2009). Scar (defined as myocardium with a signal intensity ≥50% of the maximum in scar tissue) was characterized in terms of percent scar and number of transmural LV scar segments in a 17-segment model. The endpoints were appropriate ICD therapy and all-cause mortality. Sixty-four patients (average age 66 ± 11 years, 51 male, median LVEF 30%) were included. During 42 ± 13 months follow-up, appropriate ICD therapy occurred in 28 patients (44%), and 14 patients (22%) died. Number of transmural scar segments (P = 0.005) and percentage LV scar (P = 0.03) were both significantly associated with appropriate ICD therapy. However, neither number of transmural scar segments (P = 0.32) or percent LV scar (P = 0.59) was significantly associated with all-cause mortality.
  
  
  CONCLUSIONS
  In this observational study, in medium-term follow-up, the extent of LV scar characterized by LGE-CMR was strongly associated with the occurrence of spontaneous ventricular arrhythmias but not all-cause mortality. We hypothesize that scar quantification by LGE-CMR may be more specific for SCD than non-SCD, and may prove a valuable tool for the selection of patients for ICD therapy.
authors.affiliation: Wessex Cardiothoracic Unit, Southampton University Hospitals NHS Trust, UK. paul.andrew.scott@btinternet.com
authors.forename: Paul A
authors.initials: PA
authors.lastname: Scott
authors.forename: James A
authors.initials: JA
authors.lastname: Rosengarten
authors.forename: David C
authors.initials: DC
authors.lastname: Murday
authors.forename: Charles R
authors.initials: CR
authors.lastname: Peebles
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Harden
authors.forename: Nick P
authors.initials: NP
authors.lastname: Curzen
authors.forename: John M
authors.initials: JM
authors.lastname: Morgan
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000209:etiology* / Q000401:mortality / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D002921:Cicatrix / Q000150:complications / Q000473:pathology* / Q000503:physiopathology; D003287:Contrast Media; D016757:Death, Sudden, Cardiac / Q000209:etiology / Q000473:pathology / Q000517:prevention & control; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000295:instrumentation; D005260:Female; D006352:Heart Ventricles / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D053208:Kaplan-Meier Estimate; D008279:Magnetic Resonance Imaging; D008297:Male; D008536:Meglumine / Q000031:analogs & derivatives*; D008875:Middle Aged; D015999:Multivariate Analysis; D009942:Organometallic Compounds; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine