title: Effect of lateral wall scar on reverse remodeling with cardiac resynchronization therapy.
abstract: BACKGROUND
  Up to 50% of patients do not respond to cardiac resynchronization therapy (CRT). Recent work has focused on quantifying left ventricular (LV) scar, with conflicting results. Some studies have shown that the global extent of LV scar is important, whereas others found the size of the septal or lateral wall scar to be key.
  
  
  OBJECTIVE
  This study sought to examine the relative importance of the size and distribution of LV scar in determining reverse remodeling to CRT.
  
  
  METHODS
  Forty-nine patients had pre-implantation rubidium-82 and fluorine-18-fluorodeoxyglucose positron emission tomography scanning. Total and regional LV scar size were calculated. Response to CRT was pre-specified as > or =10% improvement in LV end-systolic volume and/or > or =5% absolute ejection fraction improvement.
  
  
  RESULTS
  Responders (n = 31) had significantly less lateral wall scar than responders (5.6% compared with 24.5%, P = .008) but a similar extent of global and septal scar. In the ischemic group, responders' median lateral wall scar size was 11.2% (IQR 0.0 to 31.2), compared with 47.8% (IQR 21.2 to 73.4) P = .052. In the ischemic group, for each 5% absolute decrease in lateral scar size, the odds ratio of being a responder was 1.87 (95% CI: 1.11 to 3.15, P = .018). In the nonischemic group, median lateral wall scar size of responders was 3.4% (IQR 0.0 to 10.3) compared with the nonresponders, 14.4% (IQR 9.0 to 27.8), P = .046.
  
  
  CONCLUSIONS
  Responders had significantly less lateral wall scar than nonresponders, but a similar extent of global and septal scar. This held true in both ischemic and nonischemic cardiomyopathy patients.
authors: University of Ottawa Heart Institute, Ottawa, Ontario, Canada. dbirnie@ottawaheart.ca
authors: David
authors: D
authors: Birnie
authors: Rob A
authors: RA
authors: DeKemp
authors: Terence D
authors: TD
authors: Ruddy
authors: Anthony S
authors: AS
authors: Tang
authors: Ann
authors: A
authors: Guo
authors: Kathryn
authors: K
authors: Williams
authors: Richard
authors: R
authors: Wassenar
authors: Michel
authors: M
authors: Lalonde
authors: Rob S
authors: RS
authors: Beanlands
mesh_terms: D000368:Aged; D002037:Bundle-Branch Block / Q000628:therapy*; D058406:Cardiac Resynchronization Therapy; D009202:Cardiomyopathies / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology* / Q000628:therapy*; D016001:Confidence Intervals; D005260:Female; D005355:Fibrosis; D019788:Fluorodeoxyglucose F18; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000150:complications; D016017:Odds Ratio; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D012372:ROC Curve; D012413:Rubidium; D018709:Statistics, Nonparametric; D015899:Tomography, Emission-Computed, Single-Photon; D020257:Ventricular Remodeling
chemical_list: D019788:Fluorodeoxyglucose F18; D012413:Rubidium