Abstract Background In patients with severe aortic stenosis or decompensated heart failure with preserved ejection fraction (HFpEF), beta-blockers are usually discontinued despite the absence of unequivocal evidence. The data on the effect of beta-blockers in patients with moderate aortic stenosis (MAS) are scarce. Aim To investigate the relationship between beta-blocker use and outcome in patients with MAS, who were hospitalized for decompensated HFpEF. Methods The current study includes 61 patients admitted for decompensated HFpEF with concomitant MAS. The mean age of the population was 82.7±7.59 years old and 41% were females. The diagnosis MAS was established on criteria including aortic valve area between 1-1.5 cm², mean gradient - 20-39 mmHg, and max velocity between 3-3.9 m/s. For those with borderline measurements, the Doppler Velocity Index (DVI) was calculated (DVI < 0.25 indicates severe aortic stenosis). All echocardiographic data were assessed by an experienced echocardiographer. Patients with previous aortic valve replacement and a severe mixed of multivalvular disease were excluded. Result The median follow-up was 52 months (interquartile range 34-63 months). During this period 38 patients (62.3%) died from any cause while 42 (68.9%) individuals experienced a composite endpoint, of all-cause death or hospitalization due to worsening HFpEF. In survivors, we observed higher prescription of beta-blockers at hospital discharge (66% vs. 34%, p<0,05) and better diastolic function than in patients with endpoints. In multivariate Cox regression analysis the use of beta-blockers (HR = 0,27; 95% CI 0,13-0,57; p<0.01) and better diastolic function, defined as higher septal e` (HR=0,76; 95% CI 0,61-0,94; p=0.01) were identified as independent predictors for both - survival and composite endpoint (Figure 1). Advanced age was recognized as an associated factor for outcomes. Conclusion In the present study, continuation of beta-blockers at discharge was independently associated with better survival in patients with decompensated HFpEF and concomitant MAS. It remains to be addressed in future studies, whether or not beta-blockers should be started in these patients or if there is any prognostic interaction between beta-blockers and aortic valve intervention for MAS.Figure 1.Kaplan-Meier survival curve