Early treatment of unstable angina.

There is considerable controversy about what is the most appropriate treatment for patients with unstable angina. Some workers suggest that a conservative approach is all that is necessary1; others support the early use of investigative techniques, angioplasty, and operation.2 Much of this conflict stems from difficulty with the exact definition of unstable angina. Ambulatory monitoring in patients with stable angina has shown that ST segment changes with and without chest pain frequently occur when the patients are apparently at rest; approximately 150% of patients with stable angina and severe coronary artery disease have nocturnal evidence of myocardial ischaemia.3 Such patients, in whom progression to an acute myocardial infarction is rare, would not normally be regarded as having unstable angina or pre-infarction. If they were to attend a casualty department, however, this would invariably be the diagnosis. At the other end of the spectrum are those patients in the early stages of acute myocardial infarction in whom there is a stuttering onset in the hours before the development of myocardial cell necrosis. The benefits to be expected from treatment and the most appropriate technique of management will be quite different in these two disparate groups of patients despite their common diagnosis of unstable angina. In patients with severe angina, treatment with nitrates, ,B blockers, and calcium antagonists would theoretically be the best approach; in contrast, in the stuttering early stages ofmyocardial infarction anything short of rapid reversal of the thrombotic process by aspirin, streptokinase, or tissue-type plasminogen activator is likely to be of little avail. Some patients will also require restoration of coronary blood flow by percutaneous transluminal angioplasty or coronary bypass graft surgery. Because of the known pathophysiological mech-