title: Electrocardiographic measurement of infarct size compared to cardiac MRI in reperfused first time ST-segment elevation myocardial infarction.
abstract: BACKGROUND
  Myocardial infarct size (IS) following ST-segment elevation myocardial infarction (STEMI) is an important prognostic factor. We assessed the Selvester 32-point QRS score from the 12-lead ECG for measurement of IS in STEMI patients receiving reperfusion therapy compared to cardiac magnetic resonance imaging (CMRI). Furthermore we sought to explore the impact of microvascular obstruction (MVO) on the scoring system, and determine factors contributing to discrepancies between CMRI IS and Selvester score.
  
  
  METHODS
  We examined 70 patients (55 men, 15 women), mean age 57±10years with a first time STEMI (46 anterior, 24 non-anterior). QRS scores were calculated early and at follow-up (mean 2±1 and 59±14days post-STEMI). Myocardial core scar size (5SD) was measured at 5.3±3.3 and 57.8±13.5days post-infarction by CMRI. MVO was determined on initial MRI. Logistic regression analysis was performed to determine factors contributing to discordant scores, defined as a difference between CMRI and Selvester IS of >6% myocardium.
  
  
  RESULTS
  QRS scoring of anterior infarcts correlated with CMRI IS both early (r=0.734, p<0.0001) and at follow-up (r=0.716, p<0.0001); however no correlation was seen among non-anterior infarcts. QRS scoring overestimated IS at all time points. There was better agreement between ECG and CMRI measured IS in patients without MVO at both time points. Anterior infarction was inversely predictive of discordant IS estimation acutely, and larger Selvester scores were predictive of inaccurate scoring at both time periods.
  
  
  CONCLUSIONS
  Selvester QRS score correlates well with CMRI IS for anterior infarcts. MVO did not independently affect the score.
authors.affiliation: Cardiology Department, Liverpool Hospital, Sydney, NSW, Australia; South Western Sydney Clinical School, The University of NSW, Sydney, NSW, Australia.
authors.forename: Lewis E
authors.initials: LE
authors.lastname: Holmes
authors.affiliation: Cardiology Department, Liverpool Hospital, Sydney, NSW, Australia; South Western Sydney Clinical School, The University of NSW, Sydney, NSW, Australia.
authors.forename: Tuan L
authors.initials: TL
authors.lastname: Nguyen
authors.affiliation: Cardiology Department, Liverpool Hospital, Sydney, NSW, Australia; South Western Sydney Clinical School, The University of NSW, Sydney, NSW, Australia.
authors.forename: Leia
authors.initials: L
authors.lastname: Hee
authors.affiliation: Cardiology Department, Liverpool Hospital, Sydney, NSW, Australia; South Western Sydney Clinical School, The University of NSW, Sydney, NSW, Australia.
authors.forename: James
authors.initials: J
authors.lastname: Otton
authors.affiliation: South Western Sydney Clinical School, The University of NSW, Sydney, NSW, Australia; Radiology Department, Liverpool Hospital, Sydney, NSW, Australia.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Moses
authors.affiliation: Cardiology Department, Liverpool Hospital, Sydney, NSW, Australia; South Western Sydney Clinical School, The University of NSW, Sydney, NSW, Australia.
authors.forename: John K
authors.initials: JK
authors.lastname: French
authors.affiliation: Cardiology Department, Liverpool Hospital, Sydney, NSW, Australia; South Western Sydney Clinical School, The University of NSW, Sydney, NSW, Australia.
authors.forename: Liza
authors.initials: L
authors.lastname: Thomas
authors.affiliation: Cardiology Department, Liverpool Hospital, Sydney, NSW, Australia; South Western Sydney Clinical School, The University of NSW, Sydney, NSW, Australia.
authors.forename: David A B
authors.initials: DA
authors.lastname: Richards
authors.affiliation: Cardiology Department, Liverpool Hospital, Sydney, NSW, Australia; South Western Sydney Clinical School, The University of NSW, Sydney, NSW, Australia. Electronic address: c.juergens@unsw.edu.au.
authors.forename: Craig P
authors.initials: CP
authors.lastname: Juergens
mesh_terms: D000368:Aged; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015425:Myocardial Reperfusion / Q000379:methods*; D000072657:ST Elevation Myocardial Infarction / Q000000981:diagnostic imaging* / Q000503:physiopathology*
keywords: Electrocardiography; Infarct size; Magnetic resonance imaging; Myocardial infarction; Selvester QRS score