title: New-onset heart failure after permanent right ventricular apical pacing in patients with acquired high-grade atrioventricular block and normal left ventricular function.
abstract: BACKGROUND
  Emerging data have suggested that right ventricular (RV) apical pacing results in progressive left ventricular (LV) dysfunction and contributes to the development of heart failure (HF). This study aimed to investigate the prevalence and clinical predictors for the development of new-onset HF after long-term RV apical pacing in patients with acquired atrioventricular (AV) block who require permanent pacing.
  
  
  METHODS
  We studied the clinical outcomes after long-term RV apical pacing for acquired AV block in 304 patients without a prior history of HF. All patients had >90% ventricular pacing as determined by device diagnostic data.
  
  
  RESULTS
  After a median follow-up of 7.8 years, 79 patients (26.0%) developed new-onset HF after RV apical pacing. Univariate Cox-regression analysis revealed that older age at the time of pacemaker implantation (P < 0.001), the presence of coronary artery disease (CAD) (P < 0.001) or atrial fibrillation (P = 0.03), VVI pacemaker (P < 0.001), wider paced QRS duration (P < 0.001), and new-onset myocardial infarction (P < 0.001) were predictors for HF. Multivariate analysis revealed that older age at implantation (Hazard ratio [HR] 1.06, 95% confidential interval [CI] 1.04-1.09, P < 0.001), CAD (HR 1.98, 95% CI 1.12-3.50, P < 0.05), and a wider paced QRS duration (HR 1.27 for each 10 ms increment, 95% CI 1.11-1.45, P = 0.001) were independent predictors of HF. Furthermore, cardiovascular mortality was significantly increased in those with HF (36.7% vs. 2.7%, P < 0.001).
  
  
  CONCLUSIONS
  After a median follow-up of 7.8 years, permanent RV apical pacing was associated with HF in 26% of patients. Elderly age at the time of implant, a wider paced QRS duration and the presence of CAD independently predicted new-onset HF. More importantly, HF after RV apical pacing was associated with a higher cardiovascular mortality.
authors.affiliation: Cardiology Division, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Hong Kong, China.
authors.forename: Xue-Hua
authors.initials: XH
authors.lastname: Zhang
authors.forename: Hua
authors.initials: H
authors.lastname: Chen
authors.forename: Chung-Wah
authors.initials: CW
authors.lastname: Siu
authors.forename: Kai-Hang
authors.initials: KH
authors.lastname: Yiu
authors.forename: Wing-Sze
authors.initials: WS
authors.lastname: Chan
authors.forename: Kathy L
authors.initials: KL
authors.lastname: Lee
authors.forename: Hon-Wah
authors.initials: HW
authors.lastname: Chan
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Lee
authors.forename: Guo-Sheng
authors.initials: GS
authors.lastname: Fu
authors.forename: Chu-Pak
authors.initials: CP
authors.lastname: Lau
authors.forename: Hung-Fat
authors.initials: HF
authors.lastname: Tse
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D054537:Atrioventricular Block / Q000503:physiopathology* / Q000628:therapy; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects* / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000209:etiology / Q000503:physiopathology* / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013997:Time Factors; D016277:Ventricular Function, Left / Q000502:physiology*; D016278:Ventricular Function, Right / Q000502:physiology*