Association of Left and Right Branch Blocks with Clinical Outcomes in Patients with Heart Failure with Preserved Ejection Fraction.

The associations of left bundle branch block (LBBB) and right bundle branch block (RBBB) with cardiovascular (CV) outcomes compared with normal QRS in heart failure patients with preserved ejection fraction (HFpEF) are unclear. We sought to determine CV morbidity, mortality, and total costs associated with LBBB and RBBB in acute HFpEF compared with those without BBB. A cross-sectional study using the 2019 NIS database analyzed adult HFpEF hospitalizations for acute heart failure, categorizing patients by LBBB, RBBB, or normal QRS. Clinical outcomes included atrial fibrillation (AF), ventricular fibrillation (VF), complete heart block (CHB), sick sinus syndrome (SSS), cardiac arrest (CA), hospitalization costs, and in-hospital mortality. Associations between BBB types and outcomes were assessed using logistic and relative risk (RR) models with propensity score weighting, validated by sensitivity analyses. A total of 334,511 hospitalizations with HFpEF including LBBB (6,818, 2%) and RBBB (7,948, 2.4%) were analyzed. Compared with normal QRS duration, LBBB was associated with VF (odds ratio [OR] = 2.47, p  < 0.001), SSS (OR = 1.72, p  < 0.001), CHB (OR = 2.77, p  < 0.001) and greater hospitalization costs (RR = 1.15, p  < 0.001) after adjusting for covariates in PS analysis. Similarly, RBBB was associated with AF (OR = 1.30, p  < 0.001), VF (OR = 1.59, p  = 0.033), SSS (OR = 1.72, p  < 0.001), CHB (OR = 2.81, p  < 0.001), CA (OR = 1.19, p  < 0.001), and higher hospitalization costs (RR = 1.08, p  < 0.001). These associations remained unchanged in multiple validation analyses even after additionally adjusting for obesity, hypertension, and diabetes. The length of stay was shorter in HFpEF with RBBB and LBBB subgroups compared with normal QRS. In hospitalizations of acute decompensated HFpEF, BBB was associated with an increased risk of CV outcomes and hospitalization costs.