title: Remote past left ventricular function before chronic right ventricular pacing predicts responses to cardiac resynchronization therapy upgrade.
abstract: BACKGROUND
  This study examined factors that could predict response to cardiac resynchronization therapy (CRT) upgrade in patients who developed heart failure (HF) after long-term right ventricular (RV) pacing.
  
  
  METHODS
  Twenty-five consecutive patients who received CRT upgrade for long-term RV pacing (RVP) were enrolled in this study. None of these patients were eligible for CRT at the moment of starting RVP. After 5.7 ± 4.0 years chronic RVP, these 25 patients developed HF symptoms and received CRT upgrade. Echocardiography was conducted at the moment of CRT upgrade and 6 months after CRT. Remote past left ventricular ejection fraction (RP-LVEF) at the moment of starting RVP was retrospectively obtained from the echocardiographic and cardiac catherization reports. Responders were defined as a reduction in LV end-systolic volume (LVESV) ≥ 15%. Their clinical and echocardiographic parameters were analyzed and compared.
  
  
  RESULTS
  Responders had significant higher RP-LVEF as compared to nonresponders (53.6 ± 16.5% vs 31.4 ± 11.6%, P = 0.002). RP-LVEF correlated with reduction in LVESV after CRT upgrade (P < 0.001). RP-LVEF ≥ 43.5% as a cutoff value predicted response to CRT upgrade with an area under the receiver-operating curve of 0.87, a sensitivity of 78%, and a specificity of 100%. Intrinsic QRS width, septal-posterior wall motion delay, or tissue Doppler-derived dyssynchrony indexes did not predict responses to CRT upgrade.
  
  
  CONCLUSIONS
  In long-term RVP patients who developed HF and received CRT upgrade, RP-LVEF ≥ 43.5% predicts good response. Conventional dyssynchrony indexes do not predict responses to CRT upgrade in these patients.
authors.affiliation: Second Section of Cardiology, Department of Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan.
authors.forename: Po-Cheng
authors.initials: PC
authors.lastname: Chang
authors.forename: Hung-Ta
authors.initials: HT
authors.lastname: Wo
authors.forename: Tien-Hsing
authors.initials: TH
authors.lastname: Chen
authors.forename: Delon
authors.initials: D
authors.lastname: Wu
authors.forename: Fen-Chiung
authors.initials: FC
authors.lastname: Lin
authors.forename: Chun-Chieh
authors.initials: CC
authors.lastname: Wang
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D002908:Chronic Disease; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000000981:diagnostic imaging* / Q000517:prevention & control*; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D011379:Prognosis; D016896:Treatment Outcome; D014463:Ultrasonography; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000209:etiology / Q000517:prevention & control*
keywords: cardiac resynchronization therapy; echocardiography; heart failure; right ventricular pacing