title: Size and transmural extent of first-time reperfused myocardial infarction assessed by cardiac magnetic resonance can be estimated by 12-lead electrocardiogram.
abstract: BACKGROUND
  The ability of the 12-lead electrocardiogram (ECG) to quantify size and transmural extent of myocardial infarction (MI) is not fully explored. Q waves are still thought of as indicative of transmural MI despite that several studies have rejected this association. We hypothesized that size and transmural extent of acute MI indeed can be estimated by QRS scoring on the 12-lead ECG using delayed, contrast-enhanced magnetic resonance imaging (DE-MRI) as gold standard and that Q waves are not predictive of transmural MI.
  
  
  METHODS
  Twenty-nine patients with first-time reperfused MI were studied. Delayed, contrast-enhanced magnetic resonance imaging was performed and 12-lead ECG was recorded 8 +/- 1 days after the acute event. Myocardial infarction size and transmurality were determined by DE-MRI and compared with Selvester QRS score from the ECG recorded on the same day.
  
  
  RESULTS
  There was a good correlation (r = 0.79, P < .001) between MI size by QRS scoring and DE-MRI. As local MI transmurality increased as assessed by DE-MRI, the local QRS score increased progressively (P < .001). There was no significant difference in the number of Q-wave-related QRS points between nontransmural and transmural MI (1.8 +/- 0.6 vs 2.9 +/- 0.4, P = .14). The global QRS score, however, differed significantly (3.1 +/- 0.8 vs 5.1 +/- 0.6, P < .05).
  
  
  CONCLUSIONS
  QRS score is significantly related to both MI size and transmurality by DE-MRI in patients with first-time reperfused MI. Presence of Q waves, however, is not indicative of transmural MI in these patients. Thus, QRS scoring could potentially be used for diagnosing and characterizing MI in patients with suspected recent MI.
authors.affiliation: Department of Clinical Physiology, Lund University Hospital, Lund, Sweden.
authors.forename: Henrik
authors.initials: H
authors.lastname: Engblom
authors.forename: Erik
authors.initials: E
authors.lastname: Hedström
authors.forename: Einar
authors.initials: E
authors.lastname: Heiberg
authors.forename: Galen S
authors.initials: GS
authors.lastname: Wagner
authors.forename: Olle
authors.initials: O
authors.lastname: Pahlm
authors.forename: Håkan
authors.initials: H
authors.lastname: Arheden
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004562:Electrocardiography / Q000295:instrumentation; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D015425:Myocardial Reperfusion; D011446:Prospective Studies