Does the presence of left bundle branch block (LBBB) independently increase long-term mortality in patients hospitalized with symptomatic heart failure?
LBBB is associated with high mortality in hospitalized heart failure patients, but this appears driven by underlying cardiac comorbidities and myocardial dysfunction rather than LBBB itself.
BACKGROUND: The purpose of this study was to assess the independent contribution of left bundle branch block (LBBB) on long-term mortality in a large cohort with symptomatic heart failure (HF) requiring hospitalization. METHODS AND RESULTS: We studied a prospective cohort of 21 685 cases of symptomatic HF requiring hospitalization in the Register of Information and Knowledge about Swedish Heart Intensive care Admissions in 1995-2003. Long-term mortality was evaluated by Logistic regression analysis, adjusted for multiple covariates that could influence long-term prognosis. LBBB was present in 20% (4395 of 21 685) of HF admissions. Patients with LBBB had a higher prevalence of cardiac comorbid conditions than patients with no LBBB. 1-, 5-, and 10-year mortality was 31.5 vs. 28.4%, 69.3 vs. 61.3%, and 90.1 vs. 84.7% for HF patients with and without respectively LBBB. When adjusting for comorbidity, LBBB was associated with increased 5-year mortality (OR, 1.21; 95% CI, 1.10-1.35; P < 0.001). When left ventricular ejection fraction was included in the analysis LBBB had no longer any independent influence on 5-mortality (OR, 0.99; 95% CI, 0.62-1.56; P = 0.953). CONCLUSION: LBBB occurs in 1/5 in HF patients requiring hospitalization and is associated with a very high mortality. However, the high long-term mortality appears to be caused by cardiac comorbidities and myocardial dysfunction rather than the LBBB per se.
Tabrizi et al. (Thu,) studied this question.