title: Abrupt withdrawal of beta-blockade therapy in patients with myocardial infarction: effects on infarct size, left ventricular function, and hospital course.
abstract: The effects of abrupt withdrawal or continuation of beta-blockade therapy during acute myocardial infarction were evaluated in 326 patients participating in the Multicenter Investigation of the Limitation of Infarct Size (MILIS). Thirty-nine patients previously receiving a beta-blocker and randomly selected for withdrawal of beta-blockers and placebo treatment during infarction (group 1) were compared with 272 patients previously untreated with beta-blockers who were also randomly assigned to placebo therapy (group 2). There were no significant differences between the two groups in MB creatine kinase isoenzyme (15.8 +/- 10.9 vs 18.2 +/- 14.4 g-eq/m2, respectively) estimates of infarct size, radionuclide-determined left ventricular ejection fractions within 18 hr of infarction (0.44 +/- 0.15 vs 0.47 +/- 0.16) or 10 days later (0.42 +/- 0.14 vs 0.47 +/- 0.16), creatine kinase-determined incidence of infarct extension (13% vs 6%), congestive heart failure (43% vs 37%), nonfatal ventricular fibrillation (5% vs 7%), or in-hospital mortality (13% vs 9%). Patients in group 1 had more recurrent ischemic chest pain (p = .002) within the first 24 hr after infarction, but not thereafter. However, this did not appear to be related to a rebound increase in systolic blood pressure, heart rate, or double product. In a separate analysis, 20 propranolol-eligible group 1 patients randomly selected for withdrawal of beta-blockade (group 3) were compared with 15 patients randomly selected for continuation of prior beta-blockade therapy (group 4). This comparison yielded similar results. These data indicate that the beta-blockade withdrawal phenomenon is not a major clinical problem in patients with acute myocardial infarction. beta-Blockade therapy can be discontinued abruptly during acute myocardial infarction if clinically indicated.
mesh_terms: D000368:Aged; D000553:Ambulatory Care; D000787:Angina Pectoris / Q000209:etiology; D001794:Blood Pressure / Q000187:drug effects; D002986:Clinical Trials as Topic; D003402:Creatine Kinase / Q000097:blood; D011756:Diphosphates; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D007527:Isoenzymes; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D011433:Propranolol / Q000009:adverse effects / Q000627:therapeutic use*; D011877:Radionuclide Imaging; D011897:Random Allocation; D013375:Substance Withdrawal Syndrome / Q000209:etiology*; D013667:Technetium; D016698:Technetium Tc 99m Pyrophosphate
chemical_list: D011756:Diphosphates; D007527:Isoenzymes; D016698:Technetium Tc 99m Pyrophosphate; D013667:Technetium; D011433:Propranolol; D003402:Creatine Kinase