Chest pain is considered the major clinical presentation of patients with acute coronary syndromes. The significant number of patients with acute coronary syndrome who do not have chest pain on initial presentation are at risk for receiving less aggressive care. Improved recognition of atypical symptoms of acute coronary syndrome may lead to more rapid treatment. Canto and associates used a retrospective review to determine the proportion of patients admitted with unstable angina pectoris who presented with atypical symptoms and to better characterize atypical presentations of the condition.

The study used data from the Alabama Unstable Angina Study of Medicare beneficiaries, which included patients hospitalized from 1993 to 1999, to review the presenting characteristics of persons with confirmed unstable angina pectoris.

Typical presentation included substernal chest pain and chest pain aggravated by exercise or relieved with rest or nitroglycerin. Atypical presentation was defined as the absence of typical presentation. Atypical presentations (see the accompanying table) were noted in more than one half of the 4,167 patient charts reviewed. These patients were less likely to have a history of myocardial infarction or hypercholes-terolemia, or a family history of heart disease, and they were less likely to be admitted with a diagnosis of unstable angina pectoris. These patients also were less likely to receive early aspirin or other antiplatelet agents, or heparin, and they less often received beta-blocker therapy on admission. There was no difference in hospital mortality between patients presenting with typical symptoms compared with patients presenting with atypical symptoms.

The authors conclude that among Medicare beneficiaries with unstable angina pectoris, more than one half have atypical presentations. Persons more likely to present with atypical characteristics include those who are older or female, who have dementia, and who have no history of myocardial infarction or hypercholesterolemia and no family history of heart disease. Physicians should be more aware of these atypical presentations for ischemic disease, especially among the elderly and in women.