Abstract
Background: Traditionally the right ventricular (RV) pacing lead is placed in the RV apex in cardiac resynchronization therapy (CRT). It is not clear whether nonapical placement of the RV lead is associated with a better response to CRT. We aimed to perform a meta-analysis of all randomized controlled trials (RCTs) that compared apical and nonapical RV lead placement in CRT. Methods: We searched PubMed, EMBASE, Cochrane, Scopus, and relevant references for studies and performed meta-analysis using random effects model. Our main outcome measures were all-cause mortality, composite of death and heart failure hospitalization, improvement in ejection fraction (EF), left ventricle end-diastolic volume (LVEDV), left ventricle end-systolic volume (LVESV), and adverse events. Results: Seven RCTs with a total population of 1641 patients (1199 apical and 492 nonapical) were included in our meta-analysis. There was no difference in all-cause mortality (5% vs 4.3%, odds ratio (OR) = 0.86; 95% confidence interval (CI) 0.45-1.64; P =.65; I2 = 11%) and a composite of death and heart failure hospitalization (14.2% vs 12.9%, OR = 0.92; 95% CI: 0.61-1.38; P =.68; I2 = 0) between apical and nonapical groups. No difference in improvement in EF (Weighted mean difference (WMD) = 0.37; 95% CI: −2.75-3.48; P =.82; I2 = 68%), change in LVEDV (WMD = 3.67; 95% CI: −4.86-12.20; P =.40; I2 = 89%) and LVESV (WMD = −1.20; 95% CI: −4.32-1.91; P =.45; I2 = 0) were noted between apical and nonapical groups. Proportion of patients achieving >15% improvement in EF was similar in both groups (OR = 0.85; 95% CI: 0.62-1.16; P =.31; I2 = 0). Conclusion: In patients with CRT, nonapical RV pacing is not associated with improved clinical and echocardiographic outcomes compared with RV apical pacing.