Left Bundle Branch Block as a Risk Factor for Heart Failure
Anna-Sophie Thein1,2, Shalini Dixit1, Elsayed Z Soliman3
1Division of Cardiology, Department of Medicine, University of California, San Francisco.
JAMA Network Open
|August 7, 2025
Summary
Left bundle branch block (LBBB) significantly increases the risk of developing heart failure (HF) and declining left ventricular ejection fraction (LVEF) in individuals with normal heart structure. Early intervention targeting LBBB may prevent HF progression.
Area of Science:
- Cardiology
- Electrophysiology
- Preventive Medicine
Background:
- Left bundle branch block (LBBB) is a known risk factor for heart failure (HF).
- The association between LBBB and HF risk in individuals with structurally normal hearts and preserved left ventricular ejection fraction (LVEF) remains under-investigated.
Purpose of the Study:
- To investigate the association between LBBB and the risk of incident HF in community-dwelling older adults with normal cardiac structure.
Main Methods:
- A longitudinal cohort study utilizing data from the Cardiovascular Health Study (1989-2013).
- Included were adults aged 65+ with normal LVEF and no prior HF diagnosis.
- Baseline LBBB presence was determined by electrocardiograms; Cox proportional hazards models assessed outcomes.
Main Results:
- Among 4541 participants, 44 (1.0%) had LBBB at baseline.
- LBBB was associated with a nearly 5-fold increased risk of incident HF (HR, 4.98) and a 4.7-fold increased odds of LVEF decline over 5 years.
- No significant increase in all-cause mortality risk was observed for individuals with LBBB.
Conclusions:
- In individuals with structurally normal hearts, LBBB is a significant predictor of incident HF and LVEF decline.
- LBBB may serve as an early indicator for interventions aimed at preventing cardiac dysfunction and HF progression.
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