Left ventricular ejection fraction is a determinant of cardiac performance after long-term conduction system pacing
Zhu-Lin Ma1,2, Cheng-Ming Ma1, Yi-Heng Yang1
1Department of Cardiology, The First Affiliated Hospital of Dalian Medical University, No. 222. Zhongshan Road, Dalian, Liaoning Province, China.
Insights
Conduction system pacing (CSP) is a safe and feasible option for patients with left bundle branch block (LBBB) and heart failure (HF), improving cardiac performance. However, outcomes were less favorable in patients with severely reduced left ventricular ejection fraction (LVEF) < 25%.
Area of Science:
- Cardiology
- Electrophysiology
- Heart Failure Management
Background:
- Left bundle branch block (LBBB) in patients with heart failure (HF) often leads to dyssynchrony and impaired cardiac function.
- Cardiac resynchronization therapy (CRT) is indicated for some patients, but conduction system pacing (CSP) offers an alternative approach.
- The efficacy of CSP in patients with LBBB and varying degrees of left ventricular ejection fraction (LVEF) requires further investigation.
Purpose of the Study:
- To evaluate the feasibility, safety, and clinical performance of CSP in patients with LBBB and LVEF ≤ 35% who are candidates for CRT.
- To compare the cardiac performance improvements after CSP between patients with LVEF < 25% and those with LVEF between 25-35%.
Main Methods:
- A consecutive series of patients with LVEF ≤ 35% and LBBB meeting CRT criteria underwent CSP between January 2018 and December 2021.
- Patients were divided into two groups based on LVEF: < 25% and 25-35%.
- Clinical outcomes, including pacing response, reverse remodeling, and heart failure rehospitalization, were compared between the groups.
Main Results:
- CSP was successfully implanted in 92.5% of patients.
- Both LVEF groups showed significant improvements in LVEF, LVEDD, LVESV, NYHA class, and QRS duration post-CSP.
- Patients with LVEF 25-35% demonstrated superior final LVEF and LVESV, and lower heart failure rehospitalization rates compared to those with LVEF < 25%.
Conclusions:
- CSP is a feasible and safe strategy for improving clinical outcomes in patients with LBBB and heart failure.
- While CSP benefits patients with LVEF < 25%, outcomes are less optimal compared to those with LVEF 25-35%.
- Timely CSP intervention may be beneficial for cardiac performance in LBBB patients with HF.
Objective:
This study aims to explore the feasibility, safety, and clinical performance of conduction system pacing (CSP) in patients with left bundle branch block (LBBB) and varying left ventricular ejection fraction (LVEF) values.
Methods:
We consecutively enrolled all patients with LVEF ≤ 35% and LBBB who met the criteria for cardiac resynchronization therapy (CRT) and underwent CSP from January 2018 to December 2021. We compared the differences in improvements in cardiac performance after CSP between patients with LVEF < 25% and those with LVEF between 25 to 35%.
Results:
CSP was successfully deployed in 74 out of 80 patients (92.50%), including 32 patients with LVEF < 25% and 42 patients with LVEF 25%-35%. The CSP response rates were similar between the two groups (71.90% vs. 90.50%, P = 0.076), as were the super-response rates (62.50% vs. 78.60%, P = 0.129) and the rates of left ventricular complete reverse remodeling (21.90% vs. 42.90%, P = 0.059) after a follow-up period of 40.81 ± 11.93 months. Significant improvements were observed in LVEF (20.50 ± 2.75% vs. 37.78 ± 13.04%, P < 0.001), left ventricular end-diastolic dimension (LVEDD) (69.56 ± 6.77 mm vs. 59.41 ± 11.00 mm, P < 0.001), left ventricular end-systolic volume (LVESV) (224.81 ± 50.65 ml vs. 134.00 ± 83.35 ml, P < 0.001), NYHA class (3.59 ± 0.48 vs. 1.78 ± 0.66, P < 0.001), and QRS duration (168.75 ± 21.52 ms vs. 117.81 ± 17.09 ms, P < 0.001) in patients with LVEF < 25%. Despite these improvements, the final LVEF (37.78 ± 13.04 vs. 46.19 ± 9.47, P = 0.003) and final LVESV (134.00 ± 83.35 vs. 70.89 ± 38.89, P = 0.001) after CSP were inferior in patients with LVEF < 25%, and the rate of rehospitalization for heart failure was higher in this group (46.90% vs. 21.40%, P = 0.021) compared to those with LVEF between 25 to 35%.
Conclusions:
CSP is feasible and safe for improving clinical outcomes in patients with LVEF < 25%. Timely CSP intervention in patients with LBBB and HF may be beneficial for cardiac performance.
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