title: Nonmechanical ST-segment alternans in Prinzmetal's angina.
mesh_terms: D000787:Angina Pectoris / Q000503:physiopathology*; D000788:Angina Pectoris, Variant / Q000503:physiopathology*; D004562:Electrocardiography; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged