title: Does electrocardiographic Q wave burden predict the extent of scarring or hibernating myocardium as quantified by positron emission tomography?
abstract: BACKGROUND
  The extent of Q wave 'burden' on electrocardiograms (ECGs) has not been correlated with the extent of scarring and hibernation as determined quantitatively by positron emission tomography (PET).
  
  
  OBJECTIVE
  A retrospective study was performed to identify if ECG Q wave burden predicts the extent of scarring or mismatch (hibernating myocardium) as defined by rubidium-82/F-18 fluorodeoxyglucose PET viability imaging.
  
  
  METHODS
  Eighty-three consecutive patients with coronary artery disease undergoing rubidium-82/F-18 fluoro-deoxyglucose viability imaging (mean age 67.9+/-11 years, with a mean ejection fraction of 27+/-7%) formed the study population. Resting ECG was interpreted for the presence or absence of Q waves using standard ECG criteria for Q wave myocardial infarction. Patients were divided into two groups based on their Q wave burden on ECG (small to moderate scar: zero to four Q waves; large scar: five or more Q waves). Automated analysis was used to calculate the extent of scarring and mismatch (hibernating myocardium) on PET as a percentage of left ventricular myocardium. Mean PET scar and mismatch scores were calculated for the two groups.
  
  
  RESULTS
  The mean PET scar scores were significantly different between the small to moderate ECG scar group (13.9+/-7.3% of the left ventricle) and the large scar group (20.6+/-8.1% of the left ventricle; P=0.001). The mismatch scores for the small to moderate scar group (4.6+/-2.8%) were not significantly different from those of the large scar group (4.05+/-2.8%; P=0.7).
  
  
  CONCLUSIONS
  ECG Q wave 'burden' was associated with the presence of scars as defined by PET but did not accurately predict the amount of hibernating myocardium.
authors.affiliation: National Cardiac PET Centre, Department of Medicine, University of Ottawa Heart Institute, Ontario.
authors.forename: Karthikeyan
authors.initials: K
authors.lastname: Ananthasubramaniam
authors.forename: Benjamin J W
authors.initials: BJ
authors.lastname: Chow
authors.forename: Terrence D
authors.initials: TD
authors.lastname: Ruddy
authors.forename: Robert
authors.initials: R
authors.lastname: deKemp
authors.forename: Ross A
authors.initials: RA
authors.lastname: Davies
authors.forename: Jean
authors.initials: J
authors.lastname: DaSilva
authors.forename: Rob S B
authors.initials: RS
authors.lastname: Beanlands
mesh_terms: D000367:Age Factors; D000368:Aged; D002921:Cicatrix / Q000473:pathology*; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000473:pathology*; D009206:Myocardium / Q000473:pathology*; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D018570:Risk Assessment; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D012737:Sex Factors; D014022:Tissue Survival