Acute intervention studies in patients with myocardial infarction using atenolol, propranolol, oxprenolol and...

The value of beta-blockade and of disopyramide phosphate in the immediate treatment of patients with suspected acute myocardial infarction was assessed in two placebo controlled trials. In the first study 388 patients with suspected acute myocardial infarction were randomly allocated to treatment with propranolol, atenolol, or placebo, and when analysed on an initial intention to treat basis there was no significant difference between the three groups in respect of the mortality at one year. In addition, there was no evidence to suggest that either atenolol, or propranolol reduced the incidence of 'serious' ventricular arrhythmias in the coronary care unit. In the second study 473 patients with suspected acute myocardial infarction were randomly allocated to treatment with oxprenolol, disopyramide phosphate, or placebo. Again no significant differences were seen with respect to the mortality at six weeks. There was, however, a significantly increased incidence of heart failure in the group which received disopyramide phosphate. Patients who received this drug also showed a reduced number of dysrhythmic episodes on 24-hour ECG recordings, but this trend did not achieve statistical significance. These results suggest that none of the three beta-blockers tested nor disopyramide phosphate is likely to reduce the mortality from acute myocardial infarction when given prophylactically, although disopyramide phosphate does reduce the incidence of 'serious' ventriicular arrhythmias.