title: Delayed enhancement magnetic resonance imaging predicts response to cardiac resynchronization therapy in patients with intraventricular dyssynchrony.
abstract: OBJECTIVE
  We evaluated the ability of delayed enhancement magnetic resonance imaging (DE-MRI) to predict clinical response to cardiac resynchronization therapy (CRT).
  
  
  BACKGROUND
  Cardiac resynchronization therapy reduces morbidity and mortality in selected heart failure patients. However, up to 30% of patients do not have a response. We hypothesized that scar burden on DE-MRI predicts response to CRT.
  
  
  METHODS
  The DE-MRI was performed on 28 heart failure patients undergoing CRT. Patients with QRS > or =120 ms, left ventricular ejection fraction < or =35%, New York Heart Association functional class II to IV, and dyssynchrony > or =60 ms were studied. Baseline and 3-month clinical follow-up, wall motion, 6-min walk, and quality of life assessment were performed. The DE-MRI was performed 10 min after 0.20 mmol/kg intravenous gadolinium. Scar measured by planimetry was correlated with response criteria.
  
  
  RESULTS
  Twenty-three patients completed the protocol (mean age 64.9 +/- 11.7 years), with 12 (52%) having a history of myocardial infarction. Thirteen (57%) patients met response criteria. Percent total scar was significantly higher in the nonresponse versus response group (median and interquartile range of 24.7% [18.1 to 48.7] vs. 1.0% [0.0 to 8.7], p = 0.0022) and predicted nonresponse by receiver-operating characteristic analysis (area = 0.94). At a cutoff value of 15%, percent total scar provided a sensitivity and specificity of 85% and 90%, respectively, for clinical response to CRT. Similarly, septal scar < or =40% provided a 100% sensitivity and specificity for response. Regression analysis showed linear correlations between percent total scar and change in each of the individual response criteria.
  
  
  CONCLUSIONS
  The DE-MRI accurately predicted clinical response to CRT. This technique offers unique information in the assessment of patients referred for CRT.
authors.affiliation: Division of Cardiology, Department of Medicine, University of Western Ontario, London, Ontario, Canada.
authors.forename: James A
authors.initials: JA
authors.lastname: White
authors.forename: Raymond
authors.initials: R
authors.lastname: Yee
authors.forename: Xiaping
authors.initials: X
authors.lastname: Yuan
authors.forename: Andrew
authors.initials: A
authors.lastname: Krahn
authors.forename: Allan
authors.initials: A
authors.lastname: Skanes
authors.forename: Michele
authors.initials: M
authors.lastname: Parker
authors.forename: George
authors.initials: G
authors.lastname: Klein
authors.forename: Maria
authors.initials: M
authors.lastname: Drangova
mesh_terms: D000368:Aged; D002303:Cardiac Output, Low / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy*; D002304:Cardiac Pacing, Artificial; D002921:Cicatrix / Q000175:diagnosis / Q000209:etiology; D004452:Echocardiography; D005260:Female; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications; D011237:Predictive Value of Tests; D013599:Systole; D013997:Time Factors; D016896:Treatment Outcome; D018754:Ventricular Dysfunction / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000628:therapy*