Prevalence, Related Factors and Association of Left Bundle Branch Block With Prognosis in Patients With Acute Heart Failure: a Simultaneous Analysis in 3 Independent Cohorts

To determine the prevalence, characteristics and association with prognosis of left bundle branch block (LBBB) in 3 different cohorts of patients with acute heart failure (AHF).; We retrospectively analyzed 12,950 patients with AHF who were included in the EAHFE (Epidemiology Acute Heart Failure Emergency), RICA (National Heart Failure Registry of the Spanish Internal Medicine Society), and BASEL-V (Basics in Acute Shortness of Breath Evaluation of Switzerland) registries. We independently analyzed the relationship between baseline and clinical characteristics and the presence of LBBB and the potential association of LBBB with 1-year all-cause mortality and a 90-day postdischarge combined endpoint (Emergency Department reconsultation, hospitalization or death). The prevalence of LBBB was 13.5% (95% confidence interval: 12.9%-14.0%). In all registries, patients with LBBB more commonly had coronary artery disease and previous episodes of AHF, were taking chronic spironolactone treatment, had lower left ventricular ejection fraction and systolic blood pressure values and higher NT-proBNP levels. There were no differences in risk for patients with LBBB in any cohort, with adjusted hazard ratios (95% confidence interval) for 1-year mortality in EAHFE/RICA/BASEL-V cohorts of 1.02 (0.89-1.17), 1.15 (0.95-1.38) and 1.32 (0.94-1.86), respectively, and for 90-day postdischarge combined endpoint of 1.00 (0.88-1.14), 1.14 (0.92-1.40) and 1.26 (0.84-1.89). These results were consistent in sensitivity analyses.; Less than 20% of patients with AHF present LBBB, which is consistently associated with cardiovascular comorbidities, reduced left ventricular ejection fraction and more severe decompensations. Nonetheless, after taking these factors into account, LBBB in patients with AHF is not associated with worse outcomes.