title: Transmural extent of acute myocardial infarction predicts long-term improvement in contractile function.
abstract: BACKGROUND
  Previous animal studies have demonstrated that the transmural extent of acute myocardial infarction defined by contrast-enhanced MRI (ceMRI) relates to early restoration of flow and future improvements in contractile function. We tested the hypothesis that ceMRI would have similar predictive value in humans.
  
  
  RESULTS
  Twenty-four patients who presented with their first myocardial infarction and were successfully revascularized underwent cine and ceMRI of their heart within 7 days (scan 1) of the peak MB band of creatine kinase. Cine MRI was repeated 8 to 12 weeks later (scan 2). The transmural extent of infarction on scan 1 and wall thickening on both scans were determined using a 72-segment model. A total of 524 of 1571 segments (33%) were dysfunctional on scan 1. Improvement in segmental contractile function on scan 2 was inversely related to the transmural extent of infarction on scan 1 (P=0.001). Improvement in global contractile function, as assessed by ejection fraction and mean wall thickening score, was not predicted by peak creatine kinase-MB (P=0.66) or by total infarct size, as defined by MRI (P=0.70). The best predictor of global improvement was the extent of dysfunctional myocardium that was not infarcted or had infarction comprising <25% of left ventricular wall thickness (P<0.005 for ejection fraction, P<0.001 for mean wall thickening score).
  
  
  CONCLUSIONS
  In patients with acute myocardial infarction, the transmural extent of infarction defined by ceMRI predicts improvement in contractile function.
authors.affiliation: Feinberg Cardiovascular Research Institute, Department of Medicine, Northwestern University Medical School, Chicago, Illinois, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Choi
authors.forename: R J
authors.initials: RJ
authors.lastname: Kim
authors.forename: G
authors.initials: G
authors.lastname: Gubernikoff
authors.forename: J D
authors.initials: JD
authors.lastname: Vargas
authors.forename: M
authors.initials: M
authors.lastname: Parker
authors.forename: R M
authors.initials: RM
authors.lastname: Judd
mesh_terms: D000328:Adult; D005260:Female; D006352:Heart Ventricles / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D009203:Myocardial Infarction / Q000473:pathology* / Q000503:physiopathology; D011237:Predictive Value of Tests; D011379:Prognosis