title: Electrocardiographic predictors of response to cardiac resynchronization therapy in patients with intraventricular conduction delay.
abstract: BACKGROUND
  Little is known about predictors of response to cardiac resynchronization therapy (CRT) in patients with intraventricular conduction delay (IVCD). The purpose of this study was to investigate the benefits of CRT and significant variables on surface electrocardiogram (ECG) to predict response to CRT in those patients.
  
  
  RESULTS
  Among the cohort of 152 CRT patients, 40 patients with IVCD were evaluated. Sixteen patients (40%) were responders. At baseline, responders had a wider QRS duration (158±18 vs. 144±18ms, P=0.02) and a higher frequency of left axis deviation (LADEV; 75% vs. 29%, P=0.004) compared with non-responders. After CRT, greater shortening of QRS duration (ΔQRS; 26±24 vs. 7±24ms, P=0.02), axis shift from LADEV to right axis deviation (RADEV; 69% vs. 13%, P<0.001), and both rightward forces in lead I and anterior forces in V1 (56% vs. 13%, P=0.003) were found more frequently in responders. Multivariable logistic regression analysis showed that LADEV at baseline, or ΔQRS and axis shift from LADEV to RADEV after CRT were independent predictors of response to CRT.
  
  
  CONCLUSIONS
  Patients with IVCD may not respond to CRT, but LADEV at baseline and reversal of ventricular activation after CRT on surface ECG could be important to predict response to CRT.
authors.affiliation: Divisions of Arrhythmia and Electrophysiology, National Cerebral and Cardiovascular Center.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Takaya
authors.forename: Takashi
authors.initials: T
authors.lastname: Noda
authors.forename: Ikutaro
authors.initials: I
authors.lastname: Nakajima
authors.forename: Yuko
authors.initials: Y
authors.lastname: Yamada
authors.forename: Koji
authors.initials: K
authors.lastname: Miyamoto
authors.forename: Hideo
authors.initials: H
authors.lastname: Okamura
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Satomi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Aiba
authors.forename: Kengo F
authors.initials: KF
authors.lastname: Kusano
authors.forename: Hideaki
authors.initials: H
authors.lastname: Kanzaki
authors.forename: Toshihisa
authors.initials: T
authors.lastname: Anzai
authors.forename: Masaharu
authors.initials: M
authors.lastname: Ishihara
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yasuda
authors.forename: Hisao
authors.initials: H
authors.lastname: Ogawa
authors.forename: Shiro
authors.initials: S
authors.lastname: Kamakura
authors.forename: Wataru
authors.initials: W
authors.lastname: Shimizu
mesh_terms: D000328:Adult; D000368:Aged; D058406:Cardiac Resynchronization Therapy; D015331:Cohort Studies; D004562:Electrocardiography; D005260:Female; D006333:Heart Failure / Q000503:physiopathology* / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests