title: Apical vs. non-apical right ventricular pacing in cardiac resynchronization therapy: a meta-analysis.
abstract: OBJECTIVE
  Cardiac resynchronization therapy (CRT) has been shown to improve outcomes in patients with heart failure. The optimal site of right ventricular (RV) stimulation in CRT has not been established. We aimed to conduct a meta-analysis of randomized-controlled trials and observational studies comparing the mid- and long-term effects of RV apical (RVA) and non-apical (RVNA) pacing on CRT outcomes.
  
  
  METHODS
  We systematically searched the Cochrane library, EMBASE, and MEDLINE databases for studies evaluating RVA vs. RVNA pacing in CRT with regards to left ventricular end-systolic volume (LVESV) reduction, functional status improvement (defined as ≥1 New York Heart Association class improvement), and the clinical outcome of mortality or cardiovascular hospitalization. Effect estimates [standardized mean difference (SMD) and odds ratio (OR) with 95% confidence intervals (CI)] were pooled using random-effect models.
  
  
  RESULTS
  Twelve studies comprising 2670 patients (1655 with an apical and 1015 with a non-apical RV lead position) were included. In meta-analyses, LVESV reduction and functional status improvement were similar in patients with RVA and RVNA pacing (SMD 0.13, 95% CI: -0.24 to 0.50, P = 0.48; OR 1.08, 95% CI: 0.81 to 1.45, P = 0.60, respectively). Data regarding mortality and hospitalizations could not be pooled due to a small number of relevant studies with significant heterogeneity.
  
  
  CONCLUSIONS
  Our meta-analysis suggests that in CRT patients the effects of RVA or RVNA pacing on LV remodelling and functional status are similar. Mortality and morbidity outcomes with different RV lead positions should be further assessed in randomized clinical trials.
authors.affiliation: Department of Cardiology, Athens Euroclinic, 9 Athanasiadou Str., 115 21 Athens, Greece.
authors.forename: Theodoros A
authors.initials: TA
authors.lastname: Zografos
authors.affiliation: Department of Medicine, Mayo Clinic, Rochester, MN, USA.
authors.forename: Konstantinos C
authors.initials: KC
authors.lastname: Siontis
authors.affiliation: Department of Cardiology, Interventional Electrocardiology and Hypertension, University Hospital, Cracow, Poland.
authors.forename: Marek
authors.initials: M
authors.lastname: Jastrzebski
authors.affiliation: University of Rochester Medical Center, Rochester, NY, USA.
authors.forename: Valentina
authors.initials: V
authors.lastname: Kutyifa
authors.affiliation: University of Rochester Medical Center, Rochester, NY, USA.
authors.forename: Helmut U
authors.initials: HU
authors.lastname: Klein
authors.affiliation: University of Rochester Medical Center, Rochester, NY, USA.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Zareba
authors.affiliation: Department of Cardiology, Athens Euroclinic, 9 Athanasiadou Str., 115 21 Athens, Greece dkatritsis@euroclinic.gr.
authors.forename: Demosthenes G
authors.initials: DG
authors.lastname: Katritsis
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000145:classification* / Q000401:mortality*; D005260:Female; D006333:Heart Failure / Q000401:mortality* / Q000517:prevention & control*; D006352:Heart Ventricles; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D064887:Observational Studies as Topic; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors; D015996:Survival Rate; D016896:Treatment Outcome
keywords: Biventricular pacing; Cardiac resynchronization therapy; Heart failure; Right ventricular lead