Conduction system pacing versus biventricular pacing in heart failure with reduced ejection fraction: a systematic review and meta-analysis of randomized clinical trials I

ABSTRACT

BACKGROUND: Biventricular pacing (BVP) has proven efficacy in treating heart failure with reduced ejection fraction (HFrEF) and ventricular dyssynchrony. Conduction system pacing (CSP), encompassing His bundle pacing (HBP) and left bundle area pacing (LBAP), has emerged as a promising alternative, but its benefits are still uncertain. METHODS: PubMed, Scopus and Cochrane databases were searched for randomized controlled trials (RCTs) that compared CSP to BVP for resynchronization therapy in patients with HFrEF and reported the outcomes of (1) paced QRS interval duration; (2) left ventricular ejection fraction (LVEF); and (3) New York Heart Association functional class (NYHA). Heterogeneity was examined with I² statistics. A random-effects model was used for all outcomes. RESULTS: We included 7 RCTs with 408 patients, of whom 200 (49%) underwent CSP. In patients undergoing CSP, there was significantly lower paced QRS duration (MD -13.34; 95% CI -24.32 to -2.36; p=0.02; Figure 1) and NYHA functional class (SMD -0.37; 95% CI -0.69 to -0.05; p=0.02; Figure 2). There was also a significant increase in LVEF in the CSP group (MD 2.06; 95% CI 0.16 to 3.97; p=0.03; Figure 3). No statistical difference was noted for LVESV (SMD -0.51; 95% CI -1.26 to 0.24; p=0.18; I²=83%), threshold for lead capture (MD -0.08; 95% CI -0.42 to 0.27; p=0.66; I²=66%), and procedure time (MD 5.99; 95% CI -15.91 to 27.89; p=0.59; I²=79%). Hospitalizations for HF were only noted in three studies, and no difference was observed between groups (9 vs 7; RR 1.02; 95% CI 0.21 to 4.90; p=0.98; I²=46%). Differences in mortality did not reach statistical significance (3 vs 8; RR 0.45; 95% CI 0.12 to 1.62; p=0.219; I²=0%). In subgroup analysis per CSP technique, there were no significant differences between groups for QRS duration and LVEF. LBAP was the main contributor for the significant difference observed in the NYHA functional class with a trend towards subgroup difference (p interaction=0.06). Although no significant difference was noted for the overall lead threshold, the LBAP subgroup had significantly lower values compared to HBP (p interaction=0.03). CONCLUSION: These findings suggest that CSP may have symptomatic, echocardiographic and electrophysiologic benefits for HFrEF patients requiring resynchronization.