AIMS: The prognostic implication of left ventricular outflow tract velocity time integral (LVOT-VTI) on admission in hospitalized heart failure with preserved ejection fraction (HFpEF) patients has not been determined. We sought to investigate whether LVOT-VTI on admission is associated with worse clinical outcomes in hospitalized patients with HFpEF. METHODS AND RESULTS: We studied consecutive 214 hospitalized HFpEF patients who had accessible LVOT-VTI data on admission, from a prospective HFpEF-specific multicentre registry. The primary outcome of interest was the composite of all-cause death and readmission due to heart failure. During a median follow-up period of 688 (interquartile range 162-810) days, the primary outcome occurred in 83 patients (39%). The optimal cut-off value of LVOT-VTI for the primary outcome estimated by receiver operating characteristic analysis was 15.8 cm. Lower LVOT-VTI was significantly associated with the primary outcome compared with higher LVOT-VTI (P = 0.005). Multivariable Cox regression analyses revealed that lower LVOT-VTI was an independent determinant of the primary outcome (hazard ratio 0.94, 95% confidence interval 0.91-0.98). In multivariable linear regression, haemoglobin level was the strongest independent determinant of LVOT-VTI among clinical parameters (β coefficient = -0.61, P = 0.007). Furthermore, patients with lower LVOT-VTI and anaemia had the worst clinical outcomes among the groups (P < 0.001). CONCLUSIONS: Lower admission LVOT-VTI was an independent determinant of worse clinical outcomes in hospitalized HFpEF patients, indicating that LVOT-VTI on admission might be useful for categorizing a low-flow HFpEF phenotype and risk stratification in hospitalized HFpEF patients.