Epidemiological and evolutionary characteristics of heart failure in patients with left bundle branch block - A Moroccan center-based study

Background: In patients with heart failure, left bundle branch block (LBBB) seems to be associated with an increased risk of cardiovascular mortality. Purpose: The purpose of this study is to determine the in-hospital outcome of congestive heart failure patients with LBBB versus those without. Methods: We conducted a prospective observational study at the Department of Intensive Care and Rhythmology at the Mohammed V Military Hospital of Rabat, where 330 patients were admitted for heart failure between January 2008 and September 2012. Screening out patients with missing data yielded a cohort of 274 patients. Among the 274 patients, only 110 had LBBB and a left ventricular ejection fraction lower than 50%. We randomly selected a subset of 110 patients diagnosed as non-LBBB to ensure a significant statistical comparison between LBBB and non-LBBB patients. We therefore considered two groups in our analysis: 110 heart failure (HF) patients with LBBB and 110 HF patients without LBBB. Patients with incomplete records were excluded. Results: Male gender was dominant in both groups (82.7% vs. 66.7%, p=. 0.005). Patients with LBBB had a higher prevalence of idiopathic dilated cardiomyopathy (39.1% vs. 4.8%, p<. 0.001); and a higher prevalence of previous hospitalization for heart failure (64.5% vs. 23.3%, p<. 0.001). The left ventricular ejection fraction was significantly lower in the group with LBBB (25.49% vs. 39.53%, p<. 0.001). Age, cardiovascular risk factors, rhythmic and thromboembolic complications did not significantly differ. In patients with LBBB, 61.8% received cardiac resynchronization therapy performed both during the index hospital stay (50.9%) and previously (10.9%). Hospital outcome was marked by 20 in-hospital deaths in the group with LBBB and eight deaths in the group without LBBB (. p=. 0.008). Conclusion: Our analysis emphasizes increased in-hospital mortality and higher disease severity, over a short period of stay, in heart failure patients with left bundle branch block.