Clinical Outcomes of Complete Left Bundle Branch Block According to Strict or Conventional Definition Criteria in
Hui-Chun Huang1, Jui Wang2, Yen-Bin Liu1
1Department of Internal Medicine, Division of Cardiology, National Taiwan University Hospital and National Taiwan University College of Medicine.
Insights
Complete left bundle branch block (cLBBB) in patients with normal ejection fraction (EF) significantly increases cardiovascular mortality and heart failure (HF) risk. Strict and conventional cLBBB criteria show similar risks for these adverse events.
Area of Science:
- Cardiology
- Electrophysiology
- Clinical Outcomes Research
Background:
- Complete left bundle branch block (cLBBB) is linked to poor outcomes in heart failure (HF) patients.
- Its impact on cardiovascular (CV) mortality in healthy adults is minimal.
- New criteria for defining strict cLBBB have been proposed.
Purpose of the Study:
- To stratify the risk of cLBBB using conventional or strict criteria in patients with normal ejection fraction (EF).
- To evaluate the association between cLBBB and adverse cardiovascular outcomes in this population.
Main Methods:
- Retrospective enrollment of patients with cLBBB and normal LVEF (>50%) from 2010-2013.
- Inclusion of a control group matched for age and sex.
- Comparison of primary outcomes: CV mortality, HF admission, EF reduction to <40%, and total mortality.
Main Results:
- 137 patients with cLBBB (118 with strict cLBBB) were analyzed; mean age 72 years, 56.2% male.
- Follow-up of 4.3 years revealed significantly higher risks of CV mortality, reduced EF, and HF admission in cLBBB patients without atrial fibrillation.
- Conventional and strict cLBBB criteria showed similar CV event risks.
Conclusions:
- In patients with normal EF and no history of atrial fibrillation, cLBBB increases the risk of CV mortality, HF admission, and reduced EF.
- Strict cLBBB definition poses a similar risk of CV events compared to conventional cLBBB.
Background:
Complete left bundle branch block (cLBBB) is associated with poor outcomes in patients with heart failure (HF) but appears to have minimal effects on cardiovascular (CV) mortality in relatively healthy adults. New criteria to define strict cLBBB have been proposed.
Objectives:
The aim of this study was to stratify the potential risk of cLBBB according to conventional or strict criteria in patients with normal ejection fraction (EF).
Methods:
Patients with cLBBB from 2010 to 2013 who underwent baseline echocardiography within 1 year and had a left ventricular ejection fraction (LVEF) > 50% were enrolled. A control group of patients without intraventricular conduction abnormalities matched for age and sex was included. Primary outcomes including CV mortality, HF admission, EF reduction of 40%, and total mortality were compared.
Results:
A total of 137 patients with cLBBB were included, of whom 118 had strict cLBBB. The mean age was 72 ± 15 years and 56.2% were men. With a median follow-up of 4.3 years, normal LVEF patients with cLBBB but without a history of atrial fibrillation had a significantly higher risk of CV mortality (p < 0.001), EF reduction to 40% (p < 0.001), and admission for HF (p < 0.001). A similar risk of CV events was noted for the patients with conventional and strict cLBBB.
Conclusions:
In patients with normal EF and without a history of atrial fibrillation, the presence of cLBBB led to a greater risk of CV mortality, HF admission and EF reduction to < 40%. Strict cLBBB carries a similar risk of CV events to conventional cLBBB.
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