Propranolol and Threatened Myocardial Infarction

Norris and his colleagues recently described protective effects of propranolol among patients with threatened myocardial infarction.1 Their report highlights the remarkably rapid evolution of recent thinking concerning protection of ischemic myocardium with beta-adrenergic blockade.Initial efforts to protect ischemic myocardium were stimulated by the hypotheses that prognosis after acute myocardial infarction depended in part on infarct size and that infarct size could be modified favorably by a reduction in oxygen requirements or augmentation of oxygen supply to jeopardized ischemic tissue.2 Results in laboratory animals and patients demonstrated protection under defined conditions as well as a relation between the extent of . . .