This woman had a panic attack. These are common, affecting more than one third of the general population each year. The etiology appears to be a combination of both biological and psychological dysfunction. The sensations and physiologic changes can be very dramatic and, in addition to the features cited in the question stem, can include dizziness, fear of going crazy, feelings of unreality, chills, abdominal distress, palpitations, shoness of breath, and trembling or shaking. Many patients who experience a panic attack are concerned that they may have a dangerous hea, lung, or brain disorder. Although the diagnosis is fairly straightforward in a younger individual with no known serious disease, the diagnostic dilemma is more difficult in an older patient, who may potentially have a true disease of these organ systems. Whereas isolated panic attacks are common, less than 1% of the population has "panic disorder," characterized by frequent panic attacks, severe anticipation anxiety about recurrent attacks, and avoidance of places in which attacks had previously been experienced. Individuals with isolated panic attacks usually need no more therapy than reassurance; those with panic disorder may be helped with antidepressants, benzodiazepines, and behavior therapy.Angina and myocardial infarction would not be expected in a 25-year-old woman, and the ischemic changes would be apparent on the ECG. Heaburn can produce chest pain, but does not usually produce increased pulse and respiratory rate. Ref: Lee T.H. (2012). Chapter 12. Chest Discomfo. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison's Principles of Internal Medicine, 18e.