title: The extent of left ventricular scar quantified by late gadolinium enhancement MRI is associated with spontaneous ventricular arrhythmias in patients with coronary artery disease and implantable cardioverter-defibrillators.
abstract: BACKGROUND
  Characterization of sudden cardiac death (SCD) risk remains a challenge in the application of implantable cardioverter-defibrillator (ICD) therapy. Late gadolinium enhancement cardiac MRI (LGE-CMR) can accurately identify myocardial scar. We performed a retrospective, single-center observational study to evaluate the association between the extent and distribution of left ventricular scar, quantified using LGE-CMR, and the burden of ventricular arrhythmias in patients with coronary artery disease and ICDs.
  
  
  RESULTS
  All patients included (2006 to 2009) had undergone LGE-CMR before ICD implantation. Scar (defined as myocardium with a signal intensity ≥50% of the maximum in scar tissue) was characterized in terms of percent scar, scar surface area, and number of transmural left ventricular scar segments. The end point was appropriate ICD therapy. Sixty-four patients (mean age, 66±11 years; male sex, 51) were included. During 19±10 months follow-up, appropriate ICD therapy occurred in 19 (30%) patients. In Cox regression analyses, both percent scar (hazard ratio per 10%, 1.75; 95% CI, 1.09 to 2.81; P=0.02) and number of transmural scar segments (hazard ratio per segment, 1.40; 95% CI, 1.15 to 1.70; P=0.001) were significantly associated with the occurrence of appropriate ICD therapy.
  
  
  CONCLUSIONS
  In this pilot study, the extent of myocardial scar characterized by LGE-CMR was significantly associated with the occurrence of spontaneous ventricular arrhythmias. We hypothesize that scar quantification by LGE-CMR may prove a valuable risk stratification tool for the occurrence of ventricular arrhythmias, which may have implications for patient selection 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: John M
authors.initials: JM
authors.lastname: Morgan
authors.forename: Nicola
authors.initials: N
authors.lastname: Carroll
authors.forename: David C
authors.initials: DC
authors.lastname: Murday
authors.forename: Paul R
authors.initials: PR
authors.lastname: Roberts
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
mesh_terms: D000368:Aged; D002921:Cicatrix / Q000175:diagnosis / Q000209:etiology; D003287:Contrast Media; D003324:Coronary Artery Disease / Q000150:complications* / Q000175:diagnosis / Q000628:therapy; D017147:Defibrillators, Implantable; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D005682:Gadolinium; D006352:Heart Ventricles / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010865:Pilot Projects; D011379:Prognosis; D011868:Radioisotopes; D012189:Retrospective Studies; D017180:Tachycardia, Ventricular / Q000150:complications* / Q000175:diagnosis / Q000628:therapy
chemical_list: D003287:Contrast Media; D011868:Radioisotopes; D005682:Gadolinium