title: Beneficial effects of right ventricular non-apical vs. apical pacing: a systematic review and meta-analysis of randomized-controlled trials.
abstract: OBJECTIVE
  Previous studies have suggested that right ventricular apical (RVA) pacing may have deleterious effects on left ventricular function. Whether right ventricular non-apical (RVNA) pacing offers a better alternative to RVA pacing is unclear. We aimed to conduct a systematic review and meta-analysis of randomized-controlled trials (RCTs) in order to compare the mid- and long-term effects of RVA and RVNA pacing.
  
  
  RESULTS
  We systematically searched the Cochrane library, EMBASE, and MEDLINE databases for RCTs comparing RVA with RVNA pacing over >2 months follow-up. Data were pooled using random-effects models. Fourteen RCTs met our inclusion criteria involving 754 patients. Compared with subjects randomized to RVA pacing, those randomized to RVNA pacing had greater left ventricular ejection fractions (LVEF) at the end of follow-up [13 RCTs: weighted mean difference (WMD) 4.27%, 95% confidence interval (CI) 1.15%, 7.40%]. RVNA had a better LVEF at the end of follow-up in RCTs with follow-up ≥12 months (WMD 7.53%, 95% CI 2.79%, 12.27%), those with <12 months of follow-up (WMD 1.95%, 95% CI 0.17%, 3.72%), and those conducted in patients with baseline LVEF ≤40-45% (WMD 3.71%, 95% CI 0.72%, 6.70%); no significant difference was observed in RCTs of patients whose baseline LVEF was preserved. Randomized-controlled trials provided inconclusive results with respect to exercise capacity, functional class, quality of life, and survival.
  
  
  CONCLUSIONS
  While RCTs suggest that LVEF is higher with RVNA than with RVA pacing, there remains a need for large RCTs to compare the safety and efficacy of RVNA and RVA pacing.
authors.affiliation: Division of Cardiology, Jewish General Hospital, Lady Davis Institute for Medical Research, McGill University, 5790 Cote-des-Neiges Road/Suite H-453, Montreal, Quebec, Canada H3S 1Y9. avidorit@gmail.com
authors.forename: Avi
authors.initials: A
authors.lastname: Shimony
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Eisenberg
authors.forename: Kristian B
authors.initials: KB
authors.lastname: Filion
authors.forename: Guy
authors.initials: G
authors.lastname: Amit
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000379:methods* / Q000401:mortality; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D016032:Randomized Controlled Trials as Topic; D013318:Stroke Volume / Q000502:physiology; D015996:Survival Rate; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000502:physiology