Conduction system versus biventricular pacing upgrades in pacing-induced cardiomyopathy: a reconstructed individual patient data meta-analysis

Background Pacing-induced cardiomyopathy (PICM) affects up to 20% of patients with chronic right ventricular pacing. Although the feasibility of conduction system pacing (CSP) upgrade in PICM has been established, direct comparisons to conventional biventricular pacing (BiVP) upgrades remain limited, with results varying across studies. Purpose To evaluate the safety and effectiveness of CSP versus BiVP upgrades in PICM patients through a PRISMA-adherent systematic review and meta-analysis. Methods We systematically searched PubMed, Embase, and Cochrane databases until February 2026 for eligible comparative studies. A composite outcome of all-cause mortality (ACM) and heart failure hospitalisations (HFH) was assessed using individual patient data (IPD) reconstructed from Kaplan-Meier curves. Log-hazard ratio (HR) transformations were used to preserve time-to-event data. Surrogate outcomes were analysed using standardised mean differences (SMDs) and risk ratios (RRs), pooled with 95% confidence intervals (CIs). Heterogeneity was assessed using I2 statistics. Results We included six observational studies comprising 456 patients (26% female, average age: 68±14.3 years), of whom 230 received CSP (66% left bundle branch area pacing, 34% His bundle pacing) and 226 BiVP. Average follow-ups ranged from 6 to 28 months, with all but one study exceeding 20 months. The composite of ACM and HFH was similar between groups (HR 0.78; 95% CI 0.38-1.58; p = 0.49; I2 = 56%; Fig. 1A). In a pre-specified sensitivity analysis of two prospective (propensity-score matched/multivariable adjusted) multicentre studies, CSP was associated with a significant reduction in the composite outcome (HR 0.53; 95% CI 0.3-0.94; p = 0.03; I2 = 0%; Fig. 1B & 1C). This was primarily driven by reduced rates of HFH (HR 0.39; 95% CI 0.17-0.9; p = 0.03; I2 = 0%; Fig. 1D). Compared to BiVP, CSP was associated with a significant reduction in QRS duration (SMD -0.91; 95% CI -1.55 to -0.28; p = 0.005) and a modest increase in left ventricular ejection fraction (SMD 0.48; 95% CI 0.02 to 0.94; p = 0.04), with shorter procedural durations (SMD -0.58; 95% CI -1.05 to -0.1; p = 0.018) and fluoroscopy times (SMD -0.71; 95% CI -1.29 to -0.13; p = 0.016). There was no difference in procedure and device-related complications between groups (RR 0.83; 95% CI 0.26-2.69; p = 0.76). Conclusion In this reconstructed IPD meta-analysis, CSP upgrades were non-inferior to biventricular cardiac resynchronisation therapy upgrades for PICM. While clinical outcomes and complication rates were similar, CSP was associated with modestly improved electromechanical synchrony, and shorter procedural and fluoroscopy durations compared to BiVP. Though prospective adjusted data suggested a potential reduction in HFH with CSP, this finding requires confirmation in randomised trials and must be interpreted with caution.Figure 1.Reconstructed IPD meta-analysesFigure 2.