CONTEXT;: The left ventricular filling pressure (LVFP) is correlated to right atrial pressure (RAP) in heart failure. We compared diagnostic value of the inferior vena cava (IVC) measurements to the one of the 2016 echocardiographic recommendations to estimate LVFP in patients with suspected heart failure with preserved ejection fraction (HFpEF). METHODS;: Invasive hemodynamics and echocardiography were obtained within 48h in 132 consecutive patients with left ventricular ejection fraction (LVEF)≥50%, and suspected pulmonary hypertension. Increased LVFP was defined by a pulmonary artery wedge pressure (PAWP)>15mmHg. RESULTS;: In 83 sinus rhythm patients, a score of the 2016 recommendations ≥ 2 (E/e’ ratio >14 and/or tricuspid regurgitation velocity>2.8m/s and/or indexed left atrial volume>34ml/m²) had a PPV of 63% for PAWP>15mmHg, whereas a dilated IVC (>2.1 cm) and/or non-collapsible (≤50%) had a PPV of 83%. The net reclassification improvement was 0.44 (p<0.05). In atrial fibrillation (AF), a dilated and/or non-collapsible IVC had an 86% PPV for PAWP>15mmHg. The correlation between RAP and PAWP was 0.60, with 75.7% concordance (100/132) between dichotomized pressures (both RAP>8 mmHg and PAWP>15mmHg and vice-versa). CONCLUSION;: The IVC size and collapsibility is valuable to identify HFpEF patients with high LVFP in both sinus rhythm and AF.Copyright © 2020. Published by Elsevier Inc.