A 59-year-old man presents to your office with a 4 week history of intermittent substernal chest discomfort with exertion, without radiation and relieved by rest. Each of several episodes lasted no more than 5 minutes. He has been in good general health, had no history of prior chest pain, hypertension, diabetes, or serious illness. He is a nonsmoker and takes no medications. Family history reveals that his father died at age 73, probably of myocardial infarction.