She observes:
  1. The pain is substernal with radiation to left shoulder and back. Cue for myocardial disease.
  2. Exertion was not a precipitating cause. Cue against myocardial disease.
  3. Patient’s pain was relieved by rest and only slightly by nitroglycerin. Evidence inconclusive or contradictory. Morphine should have decreased pain substantially.
  4. The initial ECG and cardiac enzymes do not support myocardial ischemia. Clues against myocardial disease.