AIMS: Right-sided filling pressure is elevated in some patients with heart failure (HF) and preserved ejection fraction (HFpEF). We hypothesized that right atrial pressure (RAP) would represent the cumulative burden of abnormalities in the left heart, pulmonary vasculature, and the right heart. METHODS AND RESULTS: Echocardiography was performed in 399 patients with HFpEF. RAP was estimated from inferior vena cava morphology and its respiratory change [estimated right atrial pressure (eRAP)], and patients were divided according to eRAP (3 or ≥8 mmHg). Patients with higher eRAP displayed more severe abnormalities in LV diastolic function as well as right heart structure and function than those with normal eRAP. Cardiac deaths or HF hospitalization occurred in 84 patients over a median follow-up of 19.0 months (interquartile range 6.7-36.9). The presence of higher eRAP was independently associated with an increased risk of the composite outcome (adjusted hazard ratio 2.20 vs. normal eRAP group, 95% confidence interval 1.34-3.62, P = 0.002). Kaplan-Meier curves separating the patients into four groups based on eRAP and E/e' ratio showed that event-free survival varied among the groups, providing an incremental prognostic value of eRAP over E/e' ratio. The classification and regression tree analysis demonstrated that eRAP was the strongest predictor of the outcome followed by right ventricular dimension, E/e' ratio, and estimated right ventricular systolic pressure, stratifying the patients into four risk groups (incident rate 8.8-72.2%). CONCLUSIONS: These data may provide new insights into the prognostic role of RAP in the complex pathophysiology of HFpEF and suggest the utility of eRAP for the risk stratification in patients with HFpEF.