title: Focal But Not Diffuse Myocardial Fibrosis Burden Quantification Using Cardiac Magnetic Resonance Imaging Predicts Left Ventricular Reverse Modeling Following Cardiac Resynchronization Therapy.
abstract: BACKGROUND
  Many heart failure patients with dyssynchrony do not reverse remodel (RR) in response to cardiac resynchronization therapy (CRT). The presence of focal and diffuse interstitial myocardial fibrosis may explain this high nonresponse rate. T1 mapping is a new cardiac magnetic resonance imaging (CMR) technique that overcomes the limitations of conventional contrast CMR and provides reliable quantitative assessment of diffuse myocardial fibrosis. The study tested the hypothesis that focal and diffuse fibrosis quantification would correlate with a lack of left ventricular (LV) RR to CRT.
  
  
  RESULTS
  In a prospective study of 48 consecutive patients (27 ischemic cardiomyopathy, 21 dilated cardiomyopathy) LV scar burdens were quantified (scar core and gray zone using late gadolinium enhancement LGE CMR; interstitial fibrosis using T1 mapping) before CRT implant. LV RR was defined by a ≥ 15% reduction in LV end-systolic volume 6 months postimplant. Twenty-seven (56%) patients were responders with RR. Association between scar quantification and LV RR was assessed using the Poisson regression model. Univariate analysis showed that QRS duration/morphology, scar core, and gray zone volumes expressed as % of LV mass and extracellular volume index (ECV) (a measure of interstitial fibrosis from T1 mapping) to be significant predictors of LV RR. Multivariable-adjusted analyses demonstrated scar core quantification (≥ 13.7% LV mass) to be the only independent predictor of LV RR (prevalence ratio 0.40, P = 0.038).
  
  
  CONCLUSIONS
  Focal scar burden detected by LGE CMR is associated with a poor response to CRT. Diffuse interstitial fibrosis assessment by T1 mapping, however, is not independently predictive of CRT response.
authors.affiliation: Division of Imaging Science and Biomedical Engineering, Kings College London, London, UK.|Department of Cardiology, Guys and St Thomas' NHS Trust, London, UK.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Division of Imaging Science and Biomedical Engineering, Kings College London, London, UK.|Department of Cardiology, Guys and St Thomas' NHS Trust, London, UK.
authors.forename: Manav
authors.initials: M
authors.lastname: Sohal
authors.affiliation: Division of Imaging Science and Biomedical Engineering, Kings College London, London, UK.|Department of Cardiology, Guys and St Thomas' NHS Trust, London, UK.
authors.forename: Eva
authors.initials: E
authors.lastname: Sammut
authors.affiliation: Division of Imaging Science and Biomedical Engineering, Kings College London, London, UK.|Department of Cardiology, Guys and St Thomas' NHS Trust, London, UK.
authors.forename: Nick
authors.initials: N
authors.lastname: Child
authors.affiliation: Division of Imaging Science and Biomedical Engineering, Kings College London, London, UK.|Department of Cardiology, Guys and St Thomas' NHS Trust, London, UK.
authors.forename: Tom
authors.initials: T
authors.lastname: Jackson
authors.affiliation: Division of Imaging Science and Biomedical Engineering, Kings College London, London, UK.|Department of Cardiology, Guys and St Thomas' NHS Trust, London, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Claridge
authors.affiliation: Department of Cardiology, Guys and St Thomas' NHS Trust, London, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Cooklin
authors.affiliation: Division of Imaging Science and Biomedical Engineering, Kings College London, London, UK.|Department of Cardiology, Guys and St Thomas' NHS Trust, London, UK.
authors.forename: Mark
authors.initials: M
authors.lastname: O'Neill
authors.affiliation: Division of Imaging Science and Biomedical Engineering, Kings College London, London, UK.|Department of Cardiology, Guys and St Thomas' NHS Trust, London, UK.
authors.forename: Matthew
authors.initials: M
authors.lastname: Wright
authors.affiliation: Division of Imaging Science and Biomedical Engineering, Kings College London, London, UK.|Department of Cardiology, Guys and St Thomas' NHS Trust, London, UK.
authors.forename: Jaswinder
authors.initials: J
authors.lastname: Gill
authors.affiliation: Division of Imaging Science and Biomedical Engineering, Kings College London, London, UK.|Department of Cardiology, Guys and St Thomas' NHS Trust, London, UK.
authors.forename: Amedeo
authors.initials: A
authors.lastname: Chiribiri
authors.affiliation: Division of Imaging Science and Biomedical Engineering, Kings College London, London, UK.
authors.forename: Tobias
authors.initials: T
authors.lastname: Schaeffter
authors.affiliation: Department of Cardiology, Guys and St Thomas' NHS Trust, London, UK.
authors.forename: Gerry
authors.initials: G
authors.lastname: Carr-White
authors.affiliation: Division of Imaging Science and Biomedical Engineering, Kings College London, London, UK.|Department of Cardiology, Guys and St Thomas' NHS Trust, London, UK.
authors.forename: Reza
authors.initials: R
authors.lastname: Razavi
authors.affiliation: Division of Imaging Science and Biomedical Engineering, Kings College London, London, UK.|Department of Cardiology, Guys and St Thomas' NHS Trust, London, UK.
authors.forename: C Aldo
authors.initials: CA
authors.lastname: Rinaldi
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy; D002311:Cardiomyopathy, Dilated / Q000150:complications / Q000473:pathology* / Q000503:physiopathology; D002921:Cicatrix / Q000150:complications / Q000473:pathology* / Q000503:physiopathology; D003287:Contrast Media; D005260:Female; D005355:Fibrosis; D006333:Heart Failure / Q000209:etiology / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology*; D009942:Organometallic Compounds; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left; D020257:Ventricular Remodeling
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C090600:gadobutrol
keywords: T1 mapping; cardiac magnetic resonance imaging; cardiac resynchronization therapy; fibrosis; reverse remodeling