title: Magnetic resonance imaging and response to cardiac resynchronization therapy: relative merits of left ventricular dyssynchrony and scar tissue.
abstract: OBJECTIVE
  To assess the relative value of a novel measure of left ventricular (LV) dyssynchrony derived from magnetic resonance imaging (MRI) and the extent of scar tissue for prediction of response to cardiac resynchronization therapy (CRT).
  
  
  RESULTS
  Thirty-five heart failure patients scheduled for CRT were included. Left ventricular dyssynchrony was defined as the standard deviation of 16 segment time-to-maximum radial wall thickness (SDt-16) obtained from a cine-set of short-axis slices. Delayed-enhanced MRI was performed for scar analysis. Echocardiography was used to determine response to CRT (reduction > or =15% in LV end-systolic volume 6 months after implantation). At follow-up, 21 patients (60%) were classified as responders. On MRI, SDt-16 was significantly higher in responders compared with non-responders (median 97 vs. 60 ms, P < 0.001), whereas the total extent of scar was larger in non-responders (median 35% vs. 3% in responders, P < 0.001). At the logistic regression analysis, SDt-16 was directly associated (OR = 6.3, 95% CI 3.1-9.9, P < 0.001) and the total extent of scar was inversely associated (OR = 0.52, 95% CI 0.43-0.87, P < 0.001) with response to CRT.
  
  
  CONCLUSIONS
  Magnetic resonance imaging offers the unique opportunity to assess LV dyssynchrony and scar extent in a single session. Both these parameters are important predictors of echocardiographic response to CRT.
authors: Department of Cardiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands.
authors: Nina Ajmone
authors: NA
authors: Marsan
authors: Jos J M
authors: JJ
authors: Westenberg
authors: Claudia
authors: C
authors: Ypenburg
authors: Rutger J
authors: RJ
authors: van Bommel
authors: Stijntje
authors: S
authors: Roes
authors: Victoria
authors: V
authors: Delgado
authors: Laurens F
authors: LF
authors: Tops
authors: Rob J
authors: RJ
authors: van der Geest
authors: Eric
authors: E
authors: Boersma
authors: Albert
authors: A
authors: de Roos
authors: Martin J
authors: MJ
authors: Schalij
authors: Jeroen J
authors: JJ
authors: Bax
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D009202:Cardiomyopathies / Q000473:pathology*; D002921:Cicatrix / Q000473:pathology*; D005260:Female; D006333:Heart Failure / Q000473:pathology / Q000628:therapy*; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis*