The effects of practolol on the dysrhythmias complicating acute ischemic heart disease

The cardioselective beta-adrenoceptor blocking agent practolol was used in the management of ventricular and supraventricular dysrhythmias associated with acute myocardial infarction in 134 patients, and in the management of these dysrhythmias in 19 atients with acute myocardial ischemia. Practolol was frequently effective in controlling ventricular dysrhythmias which occurred within the first 24 hours after the onset of symptoms of acute myocardial infarction. It was also effective in controlling the ventricular dysrhythmias which occurred after resuscitation from ventricular fibrillation. It was of particular value when therapeutic doses of lidocaine had been ineffective. Practolol was much less effective in controlling ventricular dysrhythmias which occurred more than 24 hours after acute infarction. Atrial fibrillation and atrial flutter were infrequently abolished by practolol in undigitalized patients after acute myocardial infarction. There was no correlation between the effectiveness of practolol and the blood concentration of the drug. One adverse effect of practolol was the occurence of sinus bradycardia with or without an increase in the frequency of ventricular ectopic beats. Bradycardia was sometimes accompanied by hypotension. Severe hypotension occasionally occurred in the absence of bradycardia.