Circulation. Heart failure
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Determining the cause for pulmonary hypertension is difficult in many patients. Pulmonary arterial hypertension (PAH) is differentiated from pulmonary venous hypertension (PVH) by a wedge pressure (PWP)>15 mm Hg in PVH. Patients undergoing right heart catheterization for evaluation of pulmonary hypertension may be dehydrated and have reduced intravascular volume, potentially leading to a falsely low measurement of PWP and an erroneous diagnosis of PAH. We hypothesized that a fluid challenge during right heart catheterization would identify occult pulmonary venous hypertension (OPVH). ⋯ Fluid challenge at the time of right heart catheterization is easily performed, safe, and identifies a large group of patients diagnosed initially with PAH, but for whom OPVH contributes to pulmonary hypertension. These results have implications for therapeutic trials in PAH and support the routine use of fluid challenge during right heart catheterization in patients with risk factors for PVH.