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Natural history and clinical significance of isolated complete left bundle branch block without associated structural

Hasan Ashraf1, Pradyumna Agasthi1, Robert J Siegel2

  • 1Department of Cardiovascular Medicine, Mayo Clinic; Phoenix, Arizona-United States.

Anatolian Journal of Cardiology
|March 10, 2021
PubMed

Insights

Isolated Left Bundle Branch Block (LBBB) without heart disease has a low risk of mortality and cardiomyopathy. This study clarifies the clinical significance of LBBB in patients without underlying cardiac conditions.

Area of Science:

  • Cardiology
  • Electrophysiology
  • Heart Failure Research

Background:

  • Left bundle branch block (LBBB) is linked to cardiac disease and may contribute to cardiomyopathy via conduction delays and dyssynchrony.
  • The independent role of LBBB in mortality and heart failure development remains unclear.
  • Previous studies have not definitively established the clinical significance of isolated LBBB.

Purpose of the Study:

  • To investigate the natural history of isolated LBBB in patients without structural heart disease.
  • To determine the clinical significance and long-term outcomes of isolated LBBB.
  • To assess the association of isolated LBBB with mortality and cardiomyopathy development.

Main Methods:

  • Retrospective chart review of patients with complete LBBB and normal echocardiograms.
  • Exclusion of patients with coronary artery disease, structural heart disease, or cardiac devices.
  • Evaluation of mortality, cardiomyopathy incidence, and heart failure hospitalizations over 1 and 10 years.

Main Results:

  • 2522 eligible patients were identified with a mean follow-up of 8.4 years.
  • 10-year mortality rate was 22.0% and cardiomyopathy incidence was 9.1%.
  • No significant difference in QRS duration was observed between deceased and alive patients, or between those with and without cardiomyopathy.

Conclusions:

  • Isolated LBBB in the absence of structural heart disease, ventricular dysfunction, or CAD is associated with a low mortality rate.
  • The incidence of cardiomyopathy is also low in patients with isolated LBBB.
  • This finding suggests that isolated LBBB may not be an independent predictor of adverse cardiac events when other cardiac pathologies are absent.
Abstract

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