ABSTRACT
BACKGROUND: Previous studies have shown that intraventricular conduction defect is associated with increased mortality in heart failure (HF) population. However, it is conflicting whether left bundle branch block (LBBB) or right bundle branch block (RBBB) is a better predictor for mortality. OBJECTIVE: To evaluate the relationship between patterns of bundle branch block (BBB) and all-cause mortality in Thai patients with chronic heart failure with reduced ejection fraction (HFrEF) and to compare the prognostic values of RBBB and LBBB in this population. MATERIAL AND METHOD: The authors retrospectively studied a cohort of 170 patients (age 58 +/- 14 years, male=117) with HFrEF requiring hospitalization and were followed-up in a heart failure clinic. Predictors of mortality were evaluated by Cox proportional hazard analysis. RESULTS: Wide QRS complex (duration >120 ms) was present in 26% of patients, 15% with LBBB, 11% with RBBB. During an average follow-up of 1.8 +/-1.6 years, 22 patients (13%) died. By univariate analysis, presence of chronic renal insufficiency, chronic obstructive pulmonary disease, severe left ventricular systolic dysfunction and RBBB, but not LBBB were associated with increased mortality. After multivariate adjustment, the presence of RBBB was the only strong predictor of mortality in HF patients (OR 3.9, 95% CI 1.3-11.7, p < 0.05). CONCLUSION: The presence of RBBB was the only independent predictor of mortality in Thai patients with HFrEE