Aims: 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.
Methods and 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.