title: Regression of fragmented QRS complex: a marker of electrical reverse remodeling in cardiac resynchronization therapy.
abstract: BACKGROUND
  Fragmented QRS (fQRS) marks inhomogeneous activation and asynchronous cardiac contraction. It has been proved that cardiac resynchronization therapy (CRT) could reverse geometrical remodeling as well as correct electrical dyssynchrony. We aimed to investigate whether fQRS changed corresponding to the therapeutic response to CRT.
  
  
  METHODS
  Patients who underwent de novo CRT implantation previously and had ≥1 follow-up between August 2012 and September 2013 in our hospital were investigated. Intrinsic electrocardiogram was recorded and fQRS in any lead was calculated. Response to CRT was defined as absolute improvement in left ventricular ejection fraction by ≥10% or by improvement >1 New York Heart Association class and without heart failure hospitalization.
  
  
  RESULTS
  A total of 75 patients (48 male, mean ages, 61 ± 9 years) were included in this study. At a median follow-up of 13 months, 57 patients had response to CRT. Responders had narrowed QRS (from 167 ± 23 ms to 158 ± 19 ms, P = 0.003) and reduced fQRS post-CRT. Nonresponders had QRS prolonging (from 151 ± 26 ms to 168 ± 16 ms, P = 0.033) and increase in fQRS. Eleven of 12 patients with reduced fQRS were responders and 8 of 12 with increased fQRS were nonresponders. Both changes in QRS and fQRS correlated strongly with CRT response (r = 0.389, P = 0.001 and r = 0.403, P = 0.000, respectively). Reduction of fQRS in ≥1 leads had high specificity (95%) in association to responders, though in low sensitivity (19%).
  
  
  CONCLUSIONS
  The changes in fQRS associated with therapeutic response to CRT. Regression of fQRS could be a maker of electrical reverse remodeling following CRT.
authors.affiliation: Center of Arrhythmia Diagnosis and Treatment, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Xin-wei
authors.initials: XW
authors.lastname: Yang
authors.forename: Wei
authors.initials: W
authors.lastname: Hua
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Zhi-min
authors.initials: ZM
authors.lastname: Liu
authors.forename: Li-gang
authors.initials: LG
authors.lastname: Ding
authors.forename: Ke-ping
authors.initials: KP
authors.lastname: Chen
authors.forename: Shu
authors.initials: S
authors.lastname: Zhang
mesh_terms: D058406:Cardiac Resynchronization Therapy / Q000706:statistics & numerical data*; D004562:Electrocardiography / Q000706:statistics & numerical data*; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000503:physiopathology* / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome
keywords: cardiac resynchronization therapy; chronic heart failure; electrical remodeling; fragmented QRS complex; response