title: Unexplained pulmonary hypertension.
mesh_terms: D006801:Humans; D006830:Hydralazine / Q000627:therapeutic use; D006976:Hypertension, Pulmonary / Q000188:drug therapy / Q000209:etiology*; D011652:Pulmonary Circulation / Q000187:drug effects
chemical_list: D006830:Hydralazine