Influence of left bundle branch block on long-term mortality in a population with heart failure

Area of Science:

• Cardiology
• Clinical Research
• Public Health

Background:

• Left bundle branch block (LBBB) is frequently observed in patients with symptomatic heart failure (HF).
• The independent prognostic value of LBBB in HF patients requiring hospitalization remains a subject of investigation.
• Understanding the specific contribution of LBBB to mortality is crucial for risk stratification and management.

Purpose of the Study:

• To determine the independent impact of LBBB on long-term mortality in a large cohort of symptomatic HF patients.
• To differentiate the effect of LBBB from confounding factors like comorbidities and myocardial function.

Main Methods:

• Prospective cohort study of 21,685 symptomatic HF admissions from the Swedish Heart Intensive care Admissions Register (1995-2003).
• Logistic regression analysis was used to evaluate long-term mortality, adjusting for multiple covariates.
• Subgroup analyses were performed, including and excluding left ventricular ejection fraction.

Main Results:

• LBBB was present in 20% of HF admissions and associated with a higher prevalence of cardiac comorbidities.
• Unadjusted analyses showed higher 1-, 5-, and 10-year mortality in HF patients with LBBB.
• After adjusting for comorbidities, LBBB was linked to increased 5-year mortality (OR, 1.21).
• However, when left ventricular ejection fraction was included, LBBB lost its independent association with 5-year mortality (OR, 0.99).

Conclusions:

• LBBB is prevalent in hospitalized HF patients and associated with high mortality.
• The increased long-term mortality in HF patients with LBBB appears primarily driven by underlying cardiac comorbidities and myocardial dysfunction, not LBBB itself.
• LBBB may serve as a marker for more severe cardiac disease rather than an independent predictor of mortality.