Abstract 4137695: Bundle Branch Block(BBB) is Independently Associated With Adverse Cardiovascular Outcomes in Patients With Heart Failure With Preserved Ejectionfraction(HFPEF): A Propensity Score Matched Analysis

Background: Ventricular dyssynchrony due to BBB can cause adverse cardiovascular(CV) outcomes in HF with reduced EF and is known to occur in HFpEF but its independent impact on is unclear. Objective: To determine if BBB is an independent risk factor for adverse HF outcomes in HFpEF and the impact of atrial fibrillation (AF).. Methods: We studied the impact of BBB in HFpEF utilizing propensity score(PS) matched cohorts without and with BBB from the TOPCAT Americas trial to account for confounding by other co-morbidities. Outcomes analyzed included the TOPCAT primary outcome, CV death&hospitalization (CVH), sudden death, pump failure death (PFD), HF hospitalizations(H), and progression of HF. The impact of concomitant AF ( defined as any AF or AF on ECG) on these outcomes with and without BBB was analyzed. Results: 329 pts with HFpEF&BBB were PS matched for 24 demographic&disease state variables, BNP strata and AF status with a cohort of 329 pts with HFpEF without BBB. BBB was associated with increased risk of the TOPCAT primary outcome (Hazard ratio{HR} 1.44, 95% confidence intervals {CI} 1.10-1.89, p=0.008), increased risk of HF hospitalizations by 41%(HR 1.41 95% CI 1.04-1.91 p=0.0248) but not CVH (HR 1.18, 95% CI 0.93-1.49, p=..169), but not sudden death (HR 1.40, 95% CI 0.70-2.82, p=0.342) or CV death (HR 1.26, 95% CI 0.84-1.89, p=0.257). Risk of pump failure death (PFD) with BBB was significantly higher in HFpEF subjects without a history of AF (Figure left panel .Kaplan Meier Log rank p=0.0478, HR: 4.22, 95% CI: 0.89 to 19.87, p=0.0689) but not in AF (p=0.138). PFD risk was markedly higher in AF subjects without BBB ( Figure right, Kaplan Meier Log rank p=.0012, HR:7.99, 95% CI:1.80 to 35.41,p = 0.0063) than those with BBB (p=0.91) Conclusion: Ventricular dysynchrony induced by BBB independently worsens HFH risk in HFpEF. Its adverse impact on PFD iis seen in the absence of AF. Increase in PFD risk with AF in HFpEF subjects is most prominent in those with normal intraventricular conduction. Mechanical dyssynchrony induced by BBB may have a role in HFpEF subgroups with preserved atrioventricular filling, leading to these adverse HF outcomes