Clinical evaluation of practolol in acute arrhythmias.

Practolol was administered in 47 instances of acute arrhythmia, mainly of supraventricular origin. The drug was highly effective in 75 per cent of cases, including those with acute myo-cardial infarction. The therapeutic dose ranged from 5 to I8o mg. Despite administration of doses up to 500 mg, no serious side effects were noted. The beta-adrenergic blocking agents are gaining increasingly wide application in the treatment of cardiac arrhythmias (Gibson and Sowton, I969). Propranolol is the best known and, heretofore, the most commonly employed drug belonging to this group. However, the usefulness of propranolol in the management of acute disturbances of the cardiac rhythm is limited owing to its direct depressant action on the myocardium, to the blockade of the beta-adrenergic receptors of the bronchial musculature, and to the action on the peripheral circulation. The purpose of the present study was the evaluation of the usefulness of one of the newer beta-adrenergic blocking agents, prac