title: Dobutamine magnetic resonance imaging predicts contractile recovery of chronically dysfunctional myocardium after successful revascularization.
abstract: OBJECTIVE
  This study sought to evaluate whether myocardial viability, as assessed by magnetic resonance imaging (MRI), reliably predicts postrevascularization left ventricular (LV) recovery.
  
  
  BACKGROUND
  Compared with positron emission tomographic findings, MRI has proved to be a reliable technique for the identification of residual myocardial viability. However, the predictive accuracy of MRI-assessed preserved end-diastolic wall thickness (DWT) and dobutamine-induced systolic wall thickening (SWT) for LV functional recovery has not yet been evaluated.
  
  
  METHODS
  Rest and low dose dobutamine MRI was performed in 43 patients with a chronic infarct (> or =4 months since ischemic event) and LV dysfunction who had undergone revascularization of the infarct-related vessel. On the basis of segmental evaluation of corresponding short-axis tomograms, infarct regions were graded viable by MRI if 1) DWT was > or =5.5 mm, and 2) dobutamine-induced SWT was > or =2 mm in > or =50% of dysfunctional segments related to the infarct region. Functional recovery was defined as SWT > or =2 mm in > or =50% of infarct-related segments at rest 4 to 6 months after successful revascularization.
  
  
  RESULTS
  Recovery of regional SWT could be observed in 27 (63%) of 43 patients. Comparison MRI grading before and after revascularization indicated that dobutamine-induced SWT was a better predictor of LV functional recovery (sensitivity 89%, specificity 94%) than was preserved DWT (sensitivity 92%, specificity 56%). Segments that remained akinetic after revascularization had significantly lower DWT (6.0+/-3.1 mm [n = 219] vs. 9.8+/-2.6 mm [n = 188], p < 0.001) than those with improved SWT. Left ventricular ejection fraction increased significantly in patients with dobutamine-induced SWT than in those with no contractile reserve (14+/-9% vs. 3+/-9%, p < 0.0002), and the magnitude of this increase was correlated with the number of dobutamine-responsive segments per infarct region (r = 0.68, p < 0.0001).
  
  
  CONCLUSIONS
  Quantitative assessment of dobutamine-induced SWT in chronic infarcts by MRI is a highly accurate predictor of LV functional recovery, and the presence of significantly reduced DWT reliably indicates irreversible myocardial damage. Therefore, dobutamine stress testing for the assessment of myocardial viability can be restricted to patients with preserved DWT.
authors.affiliation: Klinik III für Innere Medizin, Universität zu Köln, Cologne, Germany. Frank.Baer@Uni-Koeln.de
authors.forename: F M
authors.initials: FM
authors.lastname: Baer
authors.forename: P
authors.initials: P
authors.lastname: Theissen
authors.forename: C A
authors.initials: CA
authors.lastname: Schneider
authors.forename: E
authors.initials: E
authors.lastname: Voth
authors.forename: U
authors.initials: U
authors.lastname: Sechtem
authors.forename: H
authors.initials: H
authors.lastname: Schicha
authors.forename: E
authors.initials: E
authors.lastname: Erdmann
mesh_terms: D000328:Adult; D000368:Aged; D002316:Cardiotonic Agents; D002908:Chronic Disease; D017023:Coronary Angiography; D004280:Dobutamine; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D009203:Myocardial Infarction / Q000503:physiopathology / Q000628:therapy*; D009204:Myocardial Revascularization; D011237:Predictive Value of Tests; D011446:Prospective Studies; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000503:physiopathology
chemical_list: D002316:Cardiotonic Agents; D004280:Dobutamine