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Long-term cardiac outcomes of conduction system pacing upgrade in patient with generator replacement indication and
Qiao Wang1, Yan-Ni Zhao1, Da-Fei Zong1
1Department of Cardiology, The First Affiliated Hospital of Dalian Medical University, No. 222. Zhongshan Road, Dalian, Liaoning, China.
Insights
Conduction system pacing (CSP) upgrades improved cardiac performance in patients with left ventricular ejection fraction (LVEF) below 50%. Patients with heart failure with mildly reduced ejection fraction (HFmrEF) showed more favorable outcomes, with no reported complications.
Area of Science:
- Cardiology
- Electrophysiology
- Heart Failure Management
Background:
- Right ventricular pacing (RVP) can negatively impact cardiac function in patients with reduced left ventricular ejection fraction (LVEF).
- Conduction system pacing (CSP) offers a potential alternative to improve cardiac resynchronization and reduce pacing-induced cardiomyopathy.
- Elective replacement indicated (ERI) procedures for pacemakers present an opportunity to assess CSP upgrades in eligible patients.
Purpose of the Study:
- To evaluate the efficacy and safety of CSP upgrades in patients with LVEF < 50% undergoing elective pacemaker replacement.
- To compare cardiac performance and lead outcomes between patients receiving CSP upgrades and those continuing with conventional pacing.
- To assess outcomes specifically in patients with heart failure with mildly reduced ejection fraction (HFmrEF) and heart failure with reduced ejection fraction (HFrEF).
Main Methods:
- Observational, retrospective cohort study of 60 patients with LVEF < 50% and RVP percentage ≥ 40% prior to pulse generator replacement.
- Patients were divided into two groups: those who underwent CSP upgrades and those who declined.
- Cardiac performance (LVEF, LVEDD, NYHA grade) and lead outcomes were compared between groups and across LVEF subgroups.
Main Results:
- CSP upgrades were successfully performed in 90.46% of eligible patients.
- Patients undergoing CSP upgrades showed comparable improvements in LVEF and LVEDD compared to those who declined, particularly in the HFmrEF group.
- No significant complications (thrombosis, infection, lead dislodgement, perforation, stroke) were reported in either group; pacing thresholds remained stable.
Conclusions:
- CSP upgrade during pulse generator replacement is associated with improved cardiac performance in patients with LVEF < 50%.
- HFmrEF patients demonstrated more favorable cardiac performance post-CSP upgrade.
- Larger randomized controlled trials are needed to confirm these findings and establish optimal timing for CSP upgrades.
Aims:
This study aimed to investigate the potential efficacy and safety of conduction system pacing (CSP) upgrades in patients indicated for elective replacement (ERI) with a left ventricular ejection fraction (LVEF) of less than 50% including those with heart failure with mildly reduced ejection fraction (HFmrEF).
Methods:
This observational, retrospective cohort study included all patients with an LVEF < 50% who had a right ventricular pacing percentage of ≥ 40% prior to pulse generator replacement from January 2018 to October 2021. Cardiac performance and lead outcomes were compared across different LVEF groups based on whether they received CSP upgrades.
Results:
A total of 60 patients were enrolled in this study, comprising 29 patients who successfully underwent CSP upgrades (29/32, 90.46%) and 31 patients who declined the upgrades. Comparable improvements in LVEF (9.00 ± 5.90% vs. 5.90 ± 3.72%, P = 0.325) and LVEDD (2.80 ± 1.95 mm vs. 3.10 ± 2.60 mm, P = 0.835) were noted in patients with HFmrEF. However, the final LVEF (53.50 ± 6.06 vs. 40.10 ± 10.20, P = 0.031) and LVEDD (48.60 ± 4.79 vs. 55.67 ± 9.80, P = 0.040) were more favorable in patients with HFmrEF compared to those with heart failure with reduced ejection fraction (HFrEF). In patients who declined CSP upgrades, NYHA grade (2.92 ± 0.79 vs. 2.75 ± 0.45, P = 0.010) and LVEF (29.50 ± 8.19% vs. 32.92 ± 5.25%, P = 0.018) decreased in patients with HFrEF, while comparable reductions in LVEF (45.84 ± 3.00% vs. 39.89 ± 10.83%, P = 0.001) and LVEDD (55.86 ± 9.62 mm vs. 50.11 ± 6.26 mm, P = 0.044) were observed in patients with HFmrEF. No complications, including thrombosis, infection, lead dislodgement, perforation, or stroke, were reported. The pacing threshold (1.25 ± 0.45 V vs. 1.57 ± 0.55 V, P = 0.129) did not differ significantly between patients with CSP upgrades and those without, following a follow-up period of 40.57 ± 8.21 months.
Conclusion:
CSP upgrade during pulse generator replacement for battery depletion was associated with improved cardiac performances in patients with LVEF less than 50%. The final cardiac performance in patients with HFmrEF is more favorable. Larger-scale randomized controlled studies are therefore necessary to validate these findings, confirm the efficacy of CSP upgrade, and establish its optimal timing.
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