title: Magnetic resonance imaging assessment of intraventricular dyssynchrony and delayed enhancement as predictors of response to cardiac resynchronization therapy in patients with heart failure of ischaemic and non-ischaemic etiologies.
abstract: OBJECTIVE
  To assess the value of dyssynchrony and myocardial viability assessment by cardiac magnetic resonance (CMR) in prediction of response to cardiac resynchronization therapy (CRT) in patients with heart failure (HF) of both ischaemic and non-ischaemic etiologies.
  
  
  METHODS
  Patients scheduled for CRT in NYHA class II-IV, left ventricular ejection fraction <35%, QRS ≥ 120 ms were included. Tagged cine and late gadolinium enhancement (LGE) images were performed. Dyssynchrony was assessed with inTag toolbox and LGE was quantified using cutoff value at half of maximal signal in the scar. Cardiopulmonary exercise test, echocardiography and blood testing for NT-proBNP levels were done at baseline and 6 months after CRT.
  
  
  RESULTS
  52 patients (age 60.3 ± 13 years) were included. 26 patients (50%) met response criteria. The ischaemic etiology of HF was more frequent (69% vs. 31%, p=0.002), the percent of LGE was higher (7.7% [0-13.5%] vs. 19.0% (0-31.9%], p=0.013), regional vector of circumferential strain variance (RVV) was lower (0.27 ± 0.08 vs. 0.34 ± 0.09, p=0.009) and uniformity of radial strain was higher (0.72 ± 0.25 vs. 0.56 ± 0.29, p=0.046) in non-responders vs. responders. Multivariate logistic regression showed that RVV predicted response to CRT (HR 2.3, 95% CI 1.02-5.02, p=0.0430) independently of LGE and the etiology of heart failure. In the subgroup of patients with ischaemic HF the extend of transmural scar within myocardium was higher in non-responders vs. responders (26.3% vs. 15.0% respectively, p=0.01) and was a predictor of response to CRT in univariable analysis (HR 0.87, 95% CI 0.77-0.98, p=0.025) providing the sensitivity of 76% and specificity of 75% at the cutoff point of 18% in the prediction of poor response to CRT. In patients with non-ischaemic HF QRS was wider (162 ms vs. 140 ms, p=0.04), regional vector of strain variance (RVV) was higher (0.39 vs. 0.25, p=0.002) and uniformity of radial strain was lower (0.52 vs. 0.80, p=0.049) in non-responders vs. responders. Univariable logistic regression showed that RVV was a predictor of response to CRT (HR 1.50, 95% CI 1.06-2.13, p=0.022), providing the sensitivity of 94% and specificity of 85% at the cutoff point of 0.31.
  
  
  CONCLUSIONS
  CMR derived parameters of dyssynchrony such as RVV may provide an additive value in prediction of response to CRT, especially in patients with non-ischaemic etiology of heart failure. In patients with ischaemic HF the transmurality of LGE is an important predictor of lack of response to CRT.
authors: Department of Coronary Artery Disease and Structural Heart Diseases, Institute of Cardiology, Warsaw, Poland. joannapetryka@hotmail.com
authors: Joanna
authors: J
authors: Petryka
authors: Jolanta
authors: J
authors: Miśko
authors: Andrzej
authors: A
authors: Przybylski
authors: Mateusz
authors: M
authors: Śpiewak
authors: Łukasz A
authors: ŁA
authors: Małek
authors: Konrad
authors: K
authors: Werys
authors: Łukasz
authors: Ł
authors: Mazurkiewicz
authors: Katarzyna
authors: K
authors: Gepner
authors: Pierre
authors: P
authors: Croisille
authors: Marcin
authors: M
authors: Demkow
authors: Witold
authors: W
authors: Rużyłło
mesh_terms: D058406:Cardiac Resynchronization Therapy; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D005682:Gadolinium / Q000008:administration & dosage; D006333:Heart Failure / Q000175:diagnosis* / Q000209:etiology / Q000517:prevention & control*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000150:complications / Q000175:diagnosis* / Q000517:prevention & control*; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000209:etiology / Q000517:prevention & control*
chemical_list: D003287:Contrast Media; D005682:Gadolinium