title: Chemistry problem.
mesh_terms: D000368:Aged; D003937:Diagnosis, Differential; D004562:Electrocardiography; D005260:Female; D006801:Humans; D006947:Hyperkalemia / Q000097:blood; D011086:Polycythemia / Q000097:blood*; D011188:Potassium / Q000097:blood*
chemical_list: D011188:Potassium