A75-year-old retired teacher presents to your clinic, complaining of severe, unrelenting anterior chest pain radiating to her back. she describes it as if someone is "ripping out her heart." it began less than an hour ago. she states she is feeling very nauseated and may pass out. she denies any trauma or recent illnesses. she states she has never had pain like this before. nothing seems to make the pain better or worse. her medical history consists of difficult-to-control hypertension and coronary artery disease requiring two stents in the past. she is a widow. she denies any alcohol, tobacco, or illegal drug use. her mother died of a stroke and her father died of a heart attack. she has one younger brother who has had bypass surgery. on examination you see an elderly female in a great deal of distress. she is lying on the table, curled up, holding her left and right arms against her chest and is restless, trying to find a comfortable position. her blood pressure is 180/110 in the right arm and 130/60 in the left arm, and her pulse is 120. her right carotid pulse is bounding but the left carotid pulse is weak. she is afebrile but her respirations are 24 times a minute. on auscultation her lungs are clear and her cardiac examination is unremarkable. you call ems and have her taken to the hospital's er for further evaluation. what disorder of the chest best describes her symptoms?